Current sensor

ABSTRACT

A current sensor includes an electrical-conduction member, a magnetoelectric converter and a shield. The shield includes a first shield and a second shield arranged such that surfaces are opposed to and spaced away from each other. A part of the electrical-conduction member and the magnetoelectric converter are located between the first shield and the second shield. The part of the electrical-conduction member located between the first and second shields extends in an extension direction that is along the surface of the first shield. In at least one of the first shield and the second shield, a center part has a length greater than lengths of opposite end parts in a lateral direction that is along the surface of the first shield and perpendicular to the extension direction. The magnetoelectric converter is located between the opposite end parts of the first and second shields in the extension direction.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of InternationalPatent Application No. PCT/JP2019/001752 filed on Jan. 22, 2019, whichdesignated the U.S. and claims the benefit of priority from JapanesePatent Application No. 2018-052959 filed on Mar. 20, 2018. The entiredisclosures of all of the above applications are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to a current sensor to detect ameasurement current to be measured.

BACKGROUND

A current detection system, such as a current sensor, generally detectsa current by converting a magnetic field caused with a current flowingthrough a bus bar into an electric signal.

SUMMARY

The present disclosure describes a current sensor including anelectrical-conduction member, a magnetoelectric converter and a shield.The shield includes a first shield and a second shield each having aplate shape, and the first shield and the second shield are arrangedsuch that surfaces are opposed to and spaced away from each other. Apart of the electrical-conduction member and the magnetoelectricconverter are located between the surface of the first shield and thesurface of the second shield. The part of the electrical-conductionmember located between the first shield and the second shield extends inan extension direction that is along the surface of the first shield.The first shield and the second shield each have a center part andopposite end parts on opposite sides of the center part in the extensiondirection. The center part of at least one of the first shield and thesecond shield has a length greater than lengths of the opposite endparts of the at least one of the first shield and the second shield in alateral direction that is along the surface of the first shield andperpendicular to the extension direction. The magnetoelectric converteris located between the opposite end parts of the first and secondshields in the extension direction.

BRIEF DESCRIPTION OF DRAWINGS

Objects, features and advantages of the present disclosure will becomemore apparent from the following detailed description made withreference to the accompanying drawings, in which:

FIG. 1 is a block diagram for explaining an in-vehicle system;

FIG. 2 is a perspective view of a first current sensor;

FIG. 3 is an exploded perspective view of the first current sensor;

FIG. 4 illustrates diagrams showing the first current sensor;

FIG. 5 illustrates diagrams showing the first current sensor;

FIG. 6 illustrates diagrams showing a wiring board;

FIG. 7 is a block diagram for explaining a sensing unit;

FIG. 8 illustrates diagrams showing an electrical-conduction bus bar;

FIG. 9 illustrates diagrams showing a first shield;

FIG. 10 illustrates diagrams showing a second shield;

FIG. 11 illustrates diagrams showing a sensor housing;

FIG. 12 illustrates diagrams for explaining a board support pin and aboard adhesion pin;

FIG. 13 is a cross-sectional view along a line XIII-XIII shown in (b) ofFIG. 12;

FIG. 14 illustrates diagrams for explaining a shield support pin and ashield adhesion pin;

FIG. 15 is a cross-sectional view along a line XV-XV shown in (b) ofFIG. 14;

FIG. 16 is a perspective view of two individual sensors;

FIG. 17 is a perspective view of a wiring case;

FIG. 18 is a perspective view for explaining assembling of theindividual sensor to the wiring case;

FIG. 19 is a perspective view of a second current sensor;

FIG. 20 illustrates diagrams showing the wiring case;

FIG. 21 illustrates diagrams showing the wiring case;

FIG. 22 illustrates diagrams showing the second current sensor;

FIG. 23 illustrates diagrams showing the second current sensor;

FIG. 24 illustrates diagrams for explaining magnetic saturation of thefirst shield;

FIG. 25 illustrates diagrams showing a result of magnetic saturationsimulation;

FIG. 26 illustrates diagrams for explaining the second shield accordingto a second embodiment;

FIG. 27 is a schematic diagram for explaining a magnetic field totransmit a shield;

FIG. 28 illustrates diagrams showing a modification of the shield;

FIG. 29 illustrates diagrams showing another modification of the shield;

FIG. 30 is a perspective view of a first current sensor according to athird embodiment;

FIG. 31 is a cross-sectional view along a line XXXI-XXXI shown in FIG.30;

FIG. 32 illustrates diagrams for explaining a fixing form of the firstcurrent sensor;

FIG. 33 illustrates diagrams showing arrangement of a magnetoelectricconverter and the electrical-conduction bus bar according to a fourthembodiment;

FIG. 34 illustrates diagrams for explaining output change of themagnetoelectric converter;

FIG. 35 is a block diagram for explaining a sensing unit according tothe fourth embodiment;

FIG. 36 is a block diagram showing a difference circuit;

FIG. 37 is a schematic diagram for explaining shielding performance of ashield according to a fifth embodiment;

FIG. 38 is a schematic diagram for explaining the shielding performanceof a shield;

FIG. 39 illustrates diagrams showing another modification of the shield;

FIG. 40 illustrates diagrams showing another modification of the shield;

FIG. 41 is a perspective view showing a modification of the secondcurrent sensor;

FIG. 42 illustrates diagrams showing another modification of the secondcurrent sensor;

FIG. 43 illustrates diagrams showing another modification of the secondcurrent sensor;

FIG. 44 is a perspective view showing assembling of an individual sensorto a wiring case; and

FIG. 45 illustrates diagrams for explaining types of detection form.

DETAILED DESCRIPTION

According to an embodiment of the present disclosure, a current sensorincludes an electrical-conduction member, a magnetoelectric converterand a shield. The electrical-conduction member allows a measurementcurrent to be measured to flow therein. The magnetoelectric converterconverts a measurement magnetic field caused by a flow of themeasurement current into an electric signal. The shield restricts anelectromagnetic noise into the magnetoelectric converter. The shieldincludes a first shield and a second shield each having a plate shape,and the first shield and the second shield are arranged such thatsurfaces are opposed to and spaced away from each other. A part of theelectrical-conduction member and the magnetoelectric converter arelocated between the surface of the first shield and the surface of thesecond shield. The part of the electrical-conduction member locatedbetween the first shield and the second shield extends in an extensiondirection that is along the surface of the first shield. The firstshield and the second shield each have a center part and opposite endparts on opposite sides of the center part in the extension direction.The center part of at least one of the first shield and the secondshield has a length greater than lengths of the opposite end parts ofthe at least one of the first shield and the second shield in a lateraldirection that is along the surface of the first shield andperpendicular to the extension direction. The magnetoelectric converteris located between the opposite end parts of the first and secondshields in the extension direction.

In such a configuration, in the at least one of the first shield and thesecond shield, the lengths of the opposite end parts is shorter thanthat of the center part in the lateral direction. Therefore, theelectromagnetic noise less enter the opposite end parts than the centerpart. As such, the electromagnetic noise less permeates from one of theopposite end parts to the other of the opposite end parts via the centerpart in the extension direction. For this reason, the center part of theat least one of the first shield and the second shield is less likely tobe magnetically saturated, and leakage of the electromagnetic noise fromthe center part of the at least one of the first shield and the secondshield can be suppressed.

In the above configuration, the magnetoelectric converter is locatedbetween the opposite end parts of the first and second shields in theextension direction. In other words, the magnetoelectric converter islocated between the center part of the first shield and the center partof the second shield. Therefore, it is less likely that electromagneticnoise leaked from the center part due to the magnetic saturation at thecenter part of the at least one of the first shield and the secondshield will enter the magnetoelectric converter. As a result, thedegradation of accuracy in the measurement current detection can besuppressed.

Hereinafter, embodiments of the present disclosure will be furtherdescribed with reference to the drawings.

First Embodiment

<In-Vehicle System>

First, an in-vehicle system 100 to which a current sensor is appliedwill be described. The in-vehicle system 100 forms a hybrid system. Asshown in FIG. 1, the in-vehicle system 100 has a battery 200, a powerconverter 300, a first motor 400, a second motor 500, an engine 600, anda power divider 700.

The in-vehicle system 100 has multiple ECUs. FIG. 1 illustrates abattery ECU 801 and an MG ECU 802 as representatives of the multipleECUs. The multiple ECUs mutually transmit and receive a signal(s) via abus wiring 800, and perform cooperative control on a hybrid vehicle.With this cooperative control, regeneration and power running of thefirst motor 400, power generation of the second motor 500, and output ofthe engine 600 and the like are controlled in correspondence with a SOCof the battery 200. SOC is an abbreviation for a state of charge. ECU isan abbreviation for an electronic control unit.

Note that the ECU has at least one calculation processing unit (CPU),and at least one memory device (MMR) as a storage medium to hold aprogram and data. The ECU is provided with a microcomputer having acomputer-readable storage medium. The storage medium is a non-transitorysubstantive storage medium to non-temporarily hold a computer-readableprogram. The storage medium may be provided by a semiconductor memory, amagnetic disk or the like. Hereinafter, the constituent elements of thein-vehicle system 100 will be individually summarized.

The battery 200 has multiple rechargeable batteries. The multiplerechargeable batteries form a serially-connected battery stack. As arechargeable battery, a lithium ion rechargeable battery, a nickel-metalhydride rechargeable battery, an organic radical battery and the likemay be employed.

The rechargeable battery generates an electromotive voltage by chemicalreaction. The rechargeable battery has a property that deteriorationaccelerates when the charge amount is too large or too small. In otherwords, the rechargeable battery has a property that deteriorationaccelerates when the SOC is overcharge or overdischarge.

The SOC of the battery 200 corresponds to the SOC of the above-describedbattery stack. The SOC of the battery stack is the total sum of the SOCsof the multiple rechargeable batteries. The overcharge and overdischargeof the SOC of the battery stack can be avoided by the above-describedcooperative control. On the other hand, the overcharge and overdischargeof the respective SOCs of the multiple rechargeable batteries can beavoided by equalization processing of equalizing the respective SOCs ofthe multiple rechargeable batteries.

The equalization processing is performed by individuallycharging/discharging the multiple rechargeable batteries. The battery200 includes a switch to individually charge/discharge the multiplerechargeable batteries. Further, the battery 200 includes a voltagesensor, a temperature sensor and the like to detect the respective SOCsof the multiple rechargeable batteries. The battery ECU 801 controls toopen and close the switch based on outputs from these sensors and afirst current sensor 11 to be described later. With this configuration,the respective SOCs of the multiple rechargeable batteries areequalized.

The power converter 300 performs power conversion between the battery200 and the first motor 400. Further, the power converter 300 alsoperforms power conversion between the battery 200 and the second motor500. The power converter 300 converts direct current power of thebattery 200 into alternating current power at a voltage levelappropriate to power running of the first motor 400 and the second motor500. The power converter 300 converts alternating current powergenerated by power generation with the first motor 400 and the secondmotor 500 into direct current power at a voltage level appropriate tocharging of the battery 200. The power converter 300 will be describedin detail later.

The first motor 400, the second motor 500, and the engine 600 areconnected to the power divider 700. The first motor 400 is directlyconnected to an output shaft of a hybrid vehicle, which is notillustrated. The rotational energy of the first motor 400 is transmittedvia the output shaft to a running wheel. On the contrary, the rotationalenergy of the running wheel is transmitted via the output shaft to thefirst motor 400.

Power running of the first motor 400 is performed with the alternatingcurrent power supplied from the power converter 300. Rotational energygenerated by the power running is distributed with the power divider 700to the engine 600 and the output shaft of the hybrid vehicle. With thisconfiguration, cranking of a crankshaft and application of a propulsiveforce to the running wheel are performed. Further, regeneration of thefirst motor 400 is performed with the rotational energy transmitted fromthe running wheel. Alternating current power generated by theregeneration is converted with the power converter 300 into directcurrent power and voltage-reduced. This direct current power is suppliedto the battery 200. Further, the direct current power is also suppliedto various electric load mounted on the hybrid vehicle.

Power generation of the second motor 500 is performed with therotational energy supplied from the engine 600. Alternating currentpower generated by the power generation is converted with the powerconverter 300 into direct current power and voltage-reduced. This directcurrent power is supplied to the battery 200 and the various electricload.

The engine 600 generates rotational energy by combustion driving usingfuel. The rotational energy is distributed via the power divider 700 tothe second motor 500 and the output shaft. With this configuration,power generation of the second motor 500 and application of a propulsiveforce to the running wheel are performed.

The power divider 700 has a planetary gear mechanism. The power divider700 has a ring gear, a planetary gear, a sun gear, and a planetarycarrier.

The ring gear has a ring shape. Multiple teeth are formed to be arrayedin a circumferential direction respectively on an outer peripheralsurface and an inner peripheral surface of the ring gear.

The planetary gear and the sun gear each have a disk shape. Multipleteeth are formed to be arrayed in the circumferential direction on therespective circumferential surfaces of the planetary gear and the sungear.

The planetary carrier has a ring shape. Multiple planetary gears areconnected to a flat surface connecting an outer peripheral surface andan inner peripheral surface of the planetary carrier. The respectiveflat surfaces of the planetary carrier and the planetary gear areopposite to each other.

The multiple planetary gears are positioned on the circumference about arotational center of the planetary carrier. The multiple planetary gearsare provided at an equal interval between adjacent gears. In the presentembodiment, three planetary gears are arrayed at an interval of 120°.

The sun gear is provided at the center of the ring gear. The innerperipheral surface of the ring gear and the outer peripheral surface ofthe sun gear are opposite to each other. Three planetary gears areprovided between the ring gear and the sun gear. The teeth of therespective three planetary gears are engaged with the respective teethof the ring gear and the sun gear. With this configuration, therespective rotation of the ring gear, the rotation of the planetarygears, the rotation of the sun gear, and the rotation of the planetarycarrier are mutually transmitted.

The output shaft of the first motor 400 is connected to the ring gear.The crankshaft of the engine 600 is connected to the planetary carrier.The output shaft of the second motor 500 is connected to the sun gear.With this configuration, the rotation speed of the first motor 400, therotation speed of the engine 600, and the rotation speed of the secondmotor 500 are in a linear relationship in an alignment chart.

Torque is generated with the ring gear and the sun gear by supplyingalternating current power from the power converter 300 to the firstmotor 400 and the second motor 500. Torque is generated with theplanetary carrier by combustion driving with the engine 600. With thisconfiguration, the power running and the regeneration of the first motor400, the power generation of the second motor 500, and the applicationof a propulsive force to the running wheel, respectively, are performed.

The behavior of the first motor 400, the behavior of the second motor500, and the behavior of the engine 600, respectively, are subjected tocooperative control with the multiple ECUs. For example, the MG ECU 802determines a target torque for the first motor 400 and the second motor500 based on the physical quantities detected with the various sensorsmounted on the hybrid vehicle and vehicle information inputted fromother ECUs, and the like. The MG ECU 802 performs vector control so asto bring the torque, respectively generated with the first motor 400 andthe second motor 500, to the target torque.

<Power Converter>

Next, the power converter 300 will be described. The power converter 300has a converter 310, a first inverter 320, and a second inverter 330.The converter 310 performs a function of stepping up and down thevoltage level of direct current power. The first inverter 320 and thesecond inverter 330 perform a function of converting direct currentpower into alternating current power. The first inverter 320 and thesecond inverter 330 perform a function of converting alternating currentpower into direct current power.

In the in-vehicle system 100, the converter 310 boosts the directcurrent power of the battery 200 to a voltage level appropriate to powerrunning of the first motor 400 and the second motor 500. The firstinverter 320 and the second inverter 330 convert the direct currentpower into alternating current power. The alternating current power issupplied to the first motor 400 and the second motor 500. Further, thefirst inverter 320 and the second inverter 330 convert the alternatingcurrent power generated with the first motor 400 and the second motor500 into direct current power. The converter 310 reduces the directcurrent power to a voltage level appropriate to charging of the battery200.

As shown in FIG. 1, the converter 310 is electrically connected via afirst power line 301 and a second power line 302 to the battery 200. Theconverter 310 is electrically connected via a third power line 303 and afourth power line 304 to the first inverter 320 and the second inverter330 respectively.

One end of the first power line 301 is electrically connected to thecathode of the battery 200. One end of the second power line 302 iselectrically connected to the anode of the battery 200. The respectiveother ends of the first power line 301 and the second power line 302 areelectrically connected to the converter 310.

A first smoothing capacitor 305 is connected to the first power line 301and the second power line 302. One of two electrodes of the firstsmoothing capacitor 305 is connected to the third power line 303, andthe other electrode is connected to the fourth power line 304.

Note that the battery 200 has a system main relay (SMR), which is notillustrated. The electric connection between the battery stack of thebattery 200 and the power converter 300 is controlled by opening andclosing of the system main relay. That is, continuation and interruptionof power supply between the battery 200 and the power converter 300 iscontrolled by the opening and closing of the system main relay.

One end of the third power line 303 is electrically connected to a highside switch 311 of the converter 310. One end of the fourth power line304 is electrically connected to the other end of the second power line302. The respective other ends of the third power line 303 and thefourth power line 304 are electrically connected to the first inverter320 and the second inverter 330 respectively.

A second smoothing capacitor 306 is connected to the third power line303 and the fourth power line 304. One of two electrodes of the secondsmoothing capacitor 306 is connected to the third power line 303, andthe other electrode is connected to the fourth power line 304.

The first inverter 320 is electrically connected via first energizationbus bar 341 to third energization bus bar 343 to first U phase statorcoil 401 to first W phase stator coil 403 of the first motor 400. Thesecond inverter 330 is electrically connected via fourth energizationbus bar 344 to sixth energization bus bar 346 to second U phase statorcoil 501 to second W phase stator coil 503 of the second motor 500.

<Converter>

The converter 310 has the high side switch 311, a low side switch 312, ahigh side diode 311 a, a low side diode 312 a, and a reactor 313. As thehigh side switch 311 and the low side switch 312, an IGBT, a powerMOSFET or the like may be employed. In the present embodiment, ann-channel type IGBT is employed as the high side switch 311 and the lowside switch 312.

Note that when the high side switch 311 and the low side switch 312 areeach provided by the MOSFET, a body diode is formed in the MOSFET.Accordingly, the high side diode 311 a and the low side diode 312 a maybe omitted. The semiconductor device forming the converter 310 may bemanufactured with a semiconductor such as Si, or a wide gapsemiconductor such SiC.

The high side diode 311 a is connected in anti-parallel to the high sideswitch 311. That is, the cathode electrode of the high side diode 311 ais connected to the collector electrode of the high side switch 311. Theanode electrode of the high side diode 311 a is connected to the emitterelectrode of the high side switch 311.

Similarly, the low side diode 312 a is connected in anti-parallel to thelow side switch 312. The cathode electrode of the low side diode 312 ais connected to the collector electrode of the low side switch 312. Theanode electrode of the low side diode 312 a is connected to the emitterelectrode of the low side switch 312.

As shown in FIG. 1, the third power line 303 is electrically connectedto the collector electrode of the high side switch 311. The emitterelectrode of the high side switch 311 and the collector electrode of thelow side switch 312 are connected to each other. The second power line302 and the fourth power line 304 are electrically connected to theemitter electrode of the low side switch 312. With this configuration,the high side switch 311 and the low side switch 312 are connected inseries, in order, from the third power line 303 toward the second powerline 302. In other words, the high side switch 311 and the low sideswitch 312 are connected in series, in order, from the third power line303 toward the fourth power line 304.

A middle point between the high side switch 311 and the low side switch312, which are connected in series, is electrically connected to one endof the reactor 313 via the energization bus bar 307. The other end ofthe reactor 313 is electrically connected to the other end of the firstpower line 301.

With the above-described configuration, the direct current power of thebattery 200 is supplied via the reactor 313 and the energization bus bar307 to the middle point between the high side switch 311 and the lowside switch 312, which are connected in series. The alternating currentpower of the motor, converted with at least one of the first inverter320 and the second inverter 330 into the direct current power, issupplied to the collector electrode of the high side switch 311. Thealternating current power of the motor, converted into the directcurrent power, is supplied via the high side switch 311, theenergization bus bar 307, and the reactor 313, to the battery 200.

In this manner, the direct current power inputted to or outputted fromthe battery 200 flows through the energization bus bar 307. When theflowing physical quantities are limited, the direct current inputted toor outputted from the battery 200 flows through the energization bus bar307.

The high side switch 311 and the low side switch 312 of the converter310 are controlled to be open and closed with the MG ECU 802. The MG ECU802 generates a control signal and outputs the control signal to a gatedriver 803. The gate driver 803 amplifies the control signal and outputsthe control signal to the gate electrode of the switch. With thisconfiguration, the MG ECU 802 steps up or down the voltage level of thedirect current power inputted into the converter 310.

The MG ECU 802 generates a pulse signal as a control signal. The MG ECU802 controls the voltage stepping up and down levels of the directcurrent power by controlling the on duty ratio and frequency of thepulse signal. The voltage stepping up and down levels are determined incorrespondence with the above-described target torque and the SOC of thebattery 200.

When the direct current power of the battery 200 is stepped up, the MGECU 802 alternately opens and closes the high side switch 311 and thelow side switch 312 respectively. For this purpose, the MG ECU 802inverts the voltage level of the control signal outputted to the highside switch 311 and the low side switch 312.

When a high level signal is inputted into the gate electrode of the highside switch 311, a low level signal is inputted into the gate electrodeof the low side switch 312. In this case, the direct current power ofthe battery 200 is supplied via the reactor 313 and the high side switch311 to the first inverter 320 and the second inverter 330. At this time,electrical energy is stored in the reactor 313 by flow of the current.Further, electric charge is stored in the second smoothing capacitor306. The second smoothing capacitor 306 is charged.

When a low level signal is inputted into the gate electrode of the highside switch 311, a high level signal is inputted into the gate electrodeof the low side switch 312. In this case, a closed loop passing throughthe first smoothing capacitor 305, the reactor 313, and the low sideswitch 312 is formed. As described above, since the electrical energy isstored in the reactor 313, the reactor 313 attempts to pass the current.The current caused by the electrical energy in the reactor 313 flowsthrough the above-described closed loop.

In this case, supply of the direct current power via the high sideswitch 311 to the first inverter 320 and the second inverter 330 stops.However, the second smoothing capacitor 306 is charged. Accordingly,electric power is supplied from the second smoothing capacitor 306 tothe first inverter 320 and the second inverter 330. The power supply tothe first inverter 320 and the second inverter 330 is continued.

Thereafter, a high level signal is inputted into the high side switch311, while a low level signal is inputted into the low side switch 312.At this time, the electrical energy stored in the reactor 313 issupplied, together with the direct current power of the battery 200, asdirect current power, to the first inverter 320 and the second inverter330. With this configuration, the direct current power of the battery200, stepped up in a time-average manner, is supplied to the firstinverter 320 and the second inverter 330. Further, the charging of thesecond smoothing capacitor 306 is recovered, and the charging amount isincreased. The voltage level of the direct current power supplied fromthe second smoothing capacitor 306 to the first inverter 320 and thesecond inverter 330 is raised.

When the direct current power supplied from at least one of the firstinverter 320 and the second inverter 330 is stepped down, the MG ECU 802fixes the control signal outputted to the low side switch 312 at the lowlevel. At the same time, the MG ECU 802 switches the control signaloutputted to the high side switch 311 to the high level and the lowlevel sequentially.

When a high level signal is inputted into the gate electrode of the highside switch 311, the direct current power of at least one of the firstinverter 320 and the second inverter 330 is supplied via the high sideswitch 311 and the reactor 313 to the battery 200.

When a low level signal is inputted into the gate electrode of the highside switch 311, the direct current power of at least one of the firstinverter 320 and the second inverter 330 is not supplied to the battery200. As a result, the direct current power reduced in a time-averagemanner is supplied to the battery 200.

To be more exact, when a high level signal is inputted into the gateelectrode of the high side switch 311 as described above, the firstsmoothing capacitor 305 is charged. Electrical energy is stored in thereactor 313. Thereafter, when a low level signal is inputted into thegate electrode of the high side switch 311 and the output voltage andtime constant of the second smoothing capacitor 306 and those of thebattery 200 are different, charging/discharging is performed between thesecond smoothing capacitor 306 and the battery 200. Further, a diode,which is not illustrated, connects the first power line 301 and thesecond power line 302. The anode electrode of the diode is connected tothe second power line 302, and the cathode electrode of the diode isconnected to the first power line 301. Accordingly, a closed looppassing through the diode, the reactor 313, and the first smoothingcapacitor 305 is formed. The current caused by the electrical energy inthe reactor 313 flows through the closed loop.

<Inverter>

The first inverter 320 has first switch 321 to sixth switch 326, andfirst diode 321 a to sixth diode 326 a. As the first switch 321 to thesixth switch 326, an IGBT, a power MOSFET or the like may be employed.In the present embodiment, an n-channel type IGBT is employed as thefirst switch 321 to the sixth switch 326. When the MOSFET is employed asthese switches, the above-described diode may be omitted. Thesemiconductor device forming the first inverter 320 may be manufacturedwith a semiconductor such as Si, or a wide gap semiconductor such asSiC.

The first diode 321 a to the sixth diode 326 a corresponding to thefirst switch 321 to the sixth switch 326 are connected in anti-parallel.That is, assuming that k is a natural number of 1 to 6, the cathodeelectrode of the k-th diode is connected to the collector electrode ofthe k-th switch. The anode electrode of the k-th diode is connected tothe emitter electrode of the k-th switch.

The first switch 321 and the second switch 322 are connected in series,in order, from the third power line 303 toward the fourth power line304. The first switch 321 and the second switch 322 form a first U phaseleg. One end of the first energization bus bar 341 is connected to amiddle point between the first switch 321 and the second switch 322. Theother end of the first energization bus bar 341 is connected to thefirst U phase stator coil 401 of the first motor 400.

The third switch 323 and the fourth switch 324 are connected in series,in order, from the third power line 303 toward the fourth power line304. The third switch 323 and the fourth switch 324 form a first V phaseleg. One end of the second energization bus bar 342 is connected to amiddle point between the third switch 323 and the fourth switch 324. Theother end of the second energization bus bar 342 is connected to thefirst V phase stator coil 402 of the first motor 400.

The fifth switch 325 and the sixth switch 326 are connected in series,in order, from the third power line 303 toward the fourth power line304. The fifth switch 325 and the sixth switch 326 form a first W phaseleg. One end of the third energization bus bar 343 is connected to amiddle point between the fifth switch 325 and the sixth switch 326. Theother end of the third energization bus bar 343 is connected to thefirst W phase stator coil 403 of the first motor 400.

The second inverter 330 has a similar configuration to that of the firstinverter 320. The second inverter 330 has seventh switch 331 to twelfthswitch 336 and seventh diode 331 a to twelfth diode 336 a.

The seventh diode 331 a to the twelfth diode 336 a corresponding to theseventh switch 331 to the twelfth switch 336 are inverselyparallel-connected. Assuming that n is a natural number of 7 to 12, thecathode electrode of the n-th diode is connected to the collectorelectrode of the n-th switch. The anode electrode of the n-th diode isconnected to the emitter electrode of the n-th switch.

The seventh switch 331 and the eighth switch 332 are connected in seriesbetween the third power line 303 and the fourth power line 304, and forma second U phase leg. One end of the fourth energization bus bar 344 isconnected to a middle point between the seventh switch 331 and theeighth switch 332. The other end of the fourth energization bus bar 344is connected to the second U phase stator coil 501 of the second motor500.

The ninth switch 333 and the tenth switch 334 are connected in seriesbetween the third power line 303 and the fourth power line 304, and forma second V phase leg. One end of the fifth energization bus bar 345 isconnected to a middle point between the ninth switch 333 and the tenthswitch 334. The other end of the fifth energization bus bar 345 isconnected to the second V phase stator coil 502 of the second motor 500.

The eleventh switch 335 and the twelfth switch 336 are connected inseries between the third power line 303 and the fourth power line 304,and form a second W phase leg. One end of the sixth energization bus bar346 is connected to a middle point between the eleventh switch 335 andthe twelfth switch 336. The other end of the sixth energization bus bar346 is connected to the second W phase stator coil 503 of the secondmotor 500.

As described above, the first inverter 320 and the second inverter 330respectively have three phase legs corresponding to the respective Uphase to W phase stator coils of the motor. The control signal of the MGECU 802, amplified with the gate driver 803, is inputted into the gateelectrode of the switch of the respective three phase legs.

When the motor is subjected to power running, the respective switchesare PWM controlled by output of the control signal from the MG ECU 802.With this configuration, a three-phase alternating current is generatedwith the inverter. When the motor generates power, the MG ECU 802 stops,for example, output of the control signal. The alternating current powergenerated by power generation with the motor passes through the diode.As a result, the alternating current power is converted into directcurrent power.

The above-described alternating current power inputted to or outputtedfrom the first motor 400 flows through the first energization bus bar341 to the third energization bus bar 343 connecting the first inverter320 to the first motor 400. Similarly, the alternating current powerinputted to or outputted from the second motor 500 flows through thefourth energization bus bar 344 to the sixth energization bus bar 346connecting the second inverter 330 to the second motor 500.

When the flowing physical quantities are limited, the alternatingcurrent inputted to or outputted from the first motor 400 flows throughthe first energization bus bar 341 to the third energization bus bar343. The alternating current inputted to or outputted from the secondmotor 500 flows through the fourth energization bus bar 344 to the sixthenergization bus bar 346.

<Current Sensor>

Next, a current sensor applied to the in-vehicle system 100 describedabove will be described.

As a current sensor, the first current sensor 11, a second currentsensor 12, and a third current sensor 13 are provided. The first currentsensor 11 detects a current which flows through the converter 310. Thesecond current sensor 12 detects a current which flows through the firstmotor 400. The third current sensor 13 detects a current which flowsthrough the second motor 500.

The first current sensor 11 is provided on the energization bus bar 307.As described above, the direct current inputted to or outputted from thebattery 200 flows through the energization bus bar 307. The firstcurrent sensor 11 detects the direct current.

The direct current detected with the first current sensor 11 is inputtedinto the battery ECU 801. The battery ECU 801 monitors the SOC of thebattery 200 based on the direct current detected with the first currentsensor 11, the voltage of the battery stack detected with a voltagesensor, which is not illustrated, and the like.

The second current sensor 12 is provided on the first energization busbar 341 to the third energization bus bar 343. As described above, thealternating current inputted to or outputted from the first motor 400flows through the first energization bus bar 341 to the thirdenergization bus bar 343. The second current sensor 12 detects thealternating current.

The alternating current detected with the second current sensor 12 isinputted into the MG ECU 802. The MG ECU 802 vector-controls the firstmotor 400 based on the alternating current detected with the secondcurrent sensor 12, the rotation angle of the first motor 400 detectedwith a rotation angle sensor, which is not illustrated, and the like.

The third current sensor 13 is provided on the fourth energization busbar 344 to the sixth energization bus bar 346. As described above, thealternating current inputted to or outputted from the second motor 500flows through the fourth energization bus bar 344 to the sixthenergization bus bar 346. The third current sensor 13 detects thealternating current.

The alternating current detected with the third current sensor 13 isinputted into the MG ECU 802. The MG ECU 802 vector-controls the secondmotor 500 based on the alternating current detected with the thirdcurrent sensor 13, the rotation angle of the second motor 500 detectedwith a rotation angle sensor, which is not illustrated, and the like.

Note that the first U phase stator coil 401, the first V phase statorcoil 402, and the first W phase stator coil 403 of the first motor 400are star-connected. Similarly, the second U phase stator coil 501, thesecond V phase stator coil 502, and the second W phase stator coil 503of the second motor 500 are star-connected. Accordingly, by detectingthe currents in the two of the three phase stator coils, it is possibleto detect the current in the remaining one phase stator coil.

A structure where these three phase stator coils are delta-connected maybe employed. In this structure, by detecting the currents in the two ofthe three phase stator coils, it is possible to detect the current inthe remaining one phase stator coil.

The second current sensor 12 is provided on two of the firstenergization bus bar 341 to the third energization bus bar 343 connectedto the first U phase stator coil 401 to the first W phase stator coil403. More specifically, the second current sensor 12 is provided on thefirst energization bus bar 341 and the second energization bus bar 342.

Accordingly, the second current sensor 12 detects the current whichflows through the first U phase stator coil 401 and the current whichflows through the first V phase stator coil 402. The MG ECU 802 detectsthe current which flows through the first W phase stator coil 403 basedon the current which flows through the first U phase stator coil 401 andthe current which flows through the first V phase stator coil 402.

Similarly, the third current sensor 13 is provided on two of the fourthenergization bus bar 344 to the sixth energization bus bar 346 connectedto the second U phase stator coil 501 to the second W phase stator coil503. More specifically, the third current sensor 13 is provided on thefourth energization bus bar 344 and the fifth energization bus bar 345.

Accordingly, the third current sensor 13 detects the current which flowsthrough the second U phase stator coil 501 and the current which flowsthrough the second V phase stator coil 502. The MG ECU 802 detects thecurrent which flows through the second W phase stator coil 503 based onthe current which flows through the second U phase stator coil 501 andthe current which flows through the second V phase stator coil 502.

The above-described direct current inputted to or outputted from thebattery 200 and the alternating currents inputted to or outputted fromthe first motor 400 and the second motor 500 respectively correspond toa measurement current to be measured. The magnetic field generated byflow of these currents corresponds to a measured magnetic field to bemeasured.

<First Current Sensor>

As described above, the first current sensor 11 is provided on theenergization bus bar 307. The energization bus bar 307 is divided into apart adjacent to the reactor 313 and a part adjacent to the high sideswitch 311 (low side switch 312). The first current sensor 11 isprovided on the energization bus bar 307, in a form of bridging thedivided parts of the energization bus bar 307. With this configuration,the current which flows through the energization bus bar 307, i.e., thedirect current inputted to or outputted from the battery 200 flowsthrough the first current sensor 11.

The configuration where the energization bus bar 307 is divided into thepart adjacent to the reactor 313 and the part adjacent to the high sideswitch 311 is merely an example. For example, when the energization busbar 307 is not divided and connected only to the high side switch 311side, the first current sensor 11 bridges the reactor 313 and theenergization bus bar 307.

As shown in FIG. 2 to FIG. 5, the first current sensor 11 has a wiringboard 20, an electrical-conduction bus bar 30, a shield 40, and a sensorhousing 50. The electrical-conduction bus bar 30 bridges theabove-described energization bus bar 307. Accordingly, the directcurrent flows through the electrical-conduction bus bar 30. Theelectrical-conduction bus bar 30 corresponds to an electrical-conductionmember.

In FIG. 4, (a) shows a top view of the first current sensor 11; (b)shows a front view of the first current sensor 11; and (c) shows abottom view of the first current sensor 11. In FIG. 5, (a) shows a frontview of the first current sensor 11; (b) shows a side view of the firstcurrent sensor 11; and (c) shows a rear view of the first current sensor11. Note that (b) of FIG. 4 and (a) of FIG. 5 show the same figure.

As clearly indicated in these figures, a part of theelectrical-conduction bus bar 30 is insert-molded in the sensor housing50. The wiring board 20 and the shield 40 are disposed in the sensorhousing 50. The sensor housing 50 is made of an insulating resinmaterial.

The wiring board 20 is fixed in the sensor housing 50 to be opposed tothe part of the electrical-conduction bus bar 30 insert-molded in thesensor housing 50. A magnetoelectric converter 25, which will bedescribed later, is mounted on the opposing part of the wiring board 20to the electrical-conduction bus bar 30. The magnetoelectric converter25 converts a magnetic field caused by the direct current which flowsthrough the electrical-conduction bus bar 30 into an electric signal.

The shield 40 has a first shield 41 and a second shield 42. The firstshield 41 and the second shield 42 are fixed, away from each other, tothe sensor housing 50. The respective mutually opposing parts of thewiring board 20 and the electrical-conduction bus bar 30 are positionedbetween the first shield 41 and the second shield 42.

The first shield 41 and the second shield 42 are made of a material withhigher magnetic permeability than that of the sensor housing 50.Accordingly, electromagnetic noise (external noise), which attempts topermeate from the outside of the first current sensor 11 into theinside, actively attempts to pass through the first shield 41 and thesecond shield 42. With this configuration, the input of the externalnoise into the magnetoelectric converter 25 is suppressed.

A connection terminal 60 shown in FIG. 4 is insert-molded in the sensorhousing 50. The connection terminal 60 is electrically and mechanicallyconnected to the wiring board 20 with solder 61. The connection terminal60 is electrically connected via a wire harness or the like to thebattery ECU 801. The electric signal converted with the magnetoelectricconverter 25 is inputted via the connection terminal 60, a wire harness(not illustrated), and the like, into the battery ECU 801.

Next, the constituent elements of the first current sensor 11 will beindividually described in detail. In the following description, threedirections in mutual orthogonal relationship are referred to as xdirection, y direction, and z direction. The x direction corresponds toa lateral direction. The y direction corresponds to an extensiondirection.

<Wiring Board>

As shown in FIG. 6, the wiring board 20 has a flat plate shape. Thewiring board 20 has a thin flat shape having a thickness in the zdirection. The wiring board 20 is formed by laminating multipleinsulating resin layers and conductive metal layers in the z direction.In the wiring board 20, an opposing surface 20 a having the largest areaand a rear surface 20 b on the rear side of the opposing surface 20 aface in the z direction. In FIG. 6, (a) shows a top view of the wiringboard 20; and (b) shows a bottom view of the wiring board 20.

A first sensing unit 21 and a second sensing unit 22 shown in (a) ofFIG. 6 and in FIG. 7 are mounted on the opposing surface 20 a of thewiring board 20. The first sensing unit 21 and the second sensing unit22 each have an ASIC 23 and a filter 24. The ASIC 23 and the filter 24are electrically connected to each other via a wiring pattern of thewiring board 20. The connection terminal 60 is electrically connected tothe wiring pattern. ASIC is an abbreviation for application specificintegrated circuit. Note that a structure where the first sensing unit21 and the second sensing unit 22 are mounted on the rear surface 20 bmay be employed.

<ASIC>

The ASIC 23 has a magnetoelectric converter 25, a processing circuit 26,a connection pin 27, and a resin section 28. The magnetoelectricconverter 25 and the processing circuit 26 are electrically connected toeach other. One end of the connection pin 27 is electrically connectedto the processing circuit 26. The other end of the connection pin 27 iselectrically and mechanically connected to the wiring board 20. A partof the connection pin 27 including the one end, the processing circuit26, and the magnetoelectric converter 25 are covered with the resinsection 28. A part of the connection pin 27 including the other end isexposed from the resin section 28.

The magnetoelectric converter 25 has multiple magnetoresistive effectelements having a resistance value variable in correspondence withmagnetic field (transmission magnetic field) which permeates themagnetoelectric converter 25 itself. In the magnetoresistive effectelement, the resistance value varies in correspondence with transmissionmagnetic field along the opposing surface 20 a. That is, the resistancevalue of the magnetoresistive effect element varies in correspondencewith a component of the transmission magnetic field along the xdirection and a component of the transmission magnetic field along the ydirection.

On the other hand, the resistance value of the magnetoresistive effectelement does not vary in correspondence with transmission magnetic fieldalong the z direction. Accordingly, even when the external noise alongthe z direction permeates the magnetoresistive effect element, theresistance value of the magnetoresistive effect element does not vary.

The magnetoresistive effect element has a pinned layer, themagnetization direction of which is fixed, a free layer, themagnetization direction of which changes in correspondence withtransmission magnetic field, and an intermediate layer provided betweenthe pinned layer and the free layer. When the intermediate layer has anon-conductive property, the magnetoresistive effect element is a giantmagnetoresistive effect element. When the intermediate layer has aconductive property, the magnetoresistive effect element is a tunnelmagnetoresistive effect element. Note that the magnetoresistive effectelement may be an anisotropic magnetoresistive effect element (AMR).Further, the magnetoelectric converter 25 may have a hall element inplace of the magnetoresistive effect element.

The resistance value of the magnetoresistive effect element varies inaccordance with angle formed with respective magnetization directions ofthe pinned layer and the free layer. The magnetization direction of thepinned layer is along the opposing surface 20 a. The magnetizationdirection of the free layer is determined based on the transmissionmagnetic field along the opposing surface 20 a. The resistance value ofthe magnetoresistive effect element is the minimum when the respectivemagnetization directions of the free layer and the fixed layer are inparallel. The resistance value of the magnetoresistive effect element isthe maximum when the respective magnetization directions of the freelayer and the fixed layer are antiparallel.

The magnetoelectric converter 25 has a first magnetoresistive effectelement 25 a and a second magnetoresistive effect element 25 b as theabove-described magnetoresistive effect elements. The magnetizationdirection of the pinned layer of the first magnetoresistive effectelement 25 a and the magnetization direction of the pinned layer of thesecond magnetoresistive effect element 25 b are different by 90°. Therelationship of increase and decrease of resistance value is invertedbetween the magnetoresistive effect element 25 a and the secondmagnetoresistive effect element 25 b. When the resistance value of oneof the first magnetoresistive effect element 25 a and the secondmagnetoresistive effect element 25 b is reduced, the resistance value ofthe other is increased by the equivalent amount to the reduced amount.

The magnetoelectric converter 25 have two first magnetoresistive effectelements 25 a and two second magnetoresistive effect elements 25 b. Thefirst magnetoresistive effect element 25 a and the secondmagnetoresistive effect element 25 b are connected in series, in order,from a power source potential toward a reference potential, to form afirst half bridge circuit. The second magnetoresistive effect element 25b and the first magnetoresistive effect element 25 a are connected inseries, in order, from the power source potential toward the referencepotential, to form a second half bridge circuit.

Between the two half bridge circuits, the arrangement order of the firstmagnetoresistive effect element 25 a and the second magnetoresistiveeffect element 25 b is inverted. Accordingly, when a middle pointpotential of one of the two half bridge circuits is lowered, a middlepoint potential of the other is raised. In the magnetoelectric converter25, a full bridge circuit is formed by combination of these two halfbridge circuits.

The magnetoelectric converter 25 has, in addition to themagnetoresistive effect elements forming the above-described full bridgecircuit, a differential amplifier 25 c, a feedback coil 25 d, and ashunt resistor 25 e. The middle point potentials of the two half bridgecircuits are inputted into an inverted input terminal and a non-invertedinput terminal of the differential amplifier 25 c. The feedback coil 25d and the shunt resistor 25 e are connected in series, in order, from anoutput terminal of the differential amplifier 25 c toward the referencepotential.

With the above-described connection configuration, an output is made incorrespondence with variation of the resistance values of the firstmagnetoresistive effect elements 25 a and the second magnetoresistiveeffect elements 25 b, forming the full bridge circuit, from the outputterminal of the differential amplifier 25 c. The variation of resistancevalue is caused by permeation of the magnetic field along the opposingsurface 20 a through the magnetoresistive effect element. The magneticfield (measurement current) caused by the current which flows throughthe electrical-conduction bus bar 30 permeates the magnetoresistiveeffect element. Accordingly, a current corresponding to the measurementcurrent flows through the input terminal of the differential amplifier25 c.

The input terminal and the output terminal of the differential amplifier25 c are connected to each other via a feedback circuit, which is notillustrated. With this configuration, virtual short-circuit occurs inthe differential amplifier 25 c. The differential amplifier 25 coperates so as to cause the inverted input terminal and the non-invertedinput terminal to have the same potential. That is, the differentialamplifier 25 c operates such that the current which flows through theinput terminal and the current which flows through the output terminalare zero. As a result, a current corresponding to the measurementcurrent (feedback current) flows from the output terminal of thedifferential amplifier 25 c.

The feedback current flows via the feedback coil 25 d and the shuntresistor 25 e between the output terminal of the differential amplifier25 c and the reference potential. An offset magnetic field is generatedin the feedback coil 25 d by the flow of the feedback current. Theoffset magnetic field permeates the magnetoelectric converter 25. Withthis permeation, the measurement current which permeates themagnetoelectric converter 25 is offset. The magnetoelectric converter 25operates so as to bring the measurement current which permeates themagnetoelectric converter 25 itself and the offset magnetic field intoequilibrium.

A feedback voltage corresponding to the current amount of the feedbackcurrent which generates the offset magnetic field is generated in amiddle point between the feedback coil 25 d and the shunt resistor 25 e.The feedback voltage is outputted as an electric signal of detection ofthe measurement current, to the processing circuit 26 at the subsequentstage.

The processing circuit 26 has an adjustment amplifier 26 a and athreshold power source 26 b. The middle point between the feedback coil25 d and the shunt resistor 25 e is connected to a non-inverted inputterminal of the adjustment amplifier 26 a. The threshold power source 26b is connected to an inverted input terminal of the adjustment amplifier26 a. With this configuration, a differential-amplified feedback voltageis outputted from the adjustment amplifier 26 a.

The respective resistance values of the first magnetoresistive effectelements 25 a and the second magnetoresistive effect elements 25 bforming the full bridge circuit each have a temperature-dependentproperty. The output of the adjustment amplifier 26 a varies inaccordance with temperature change. The processing circuit 26 has atemperature detection element (not illustrated), a nonvolatile memory tostore the relationship between the temperature and the resistance valueof the magnetoresistive effect element, and the like. The nonvolatilememory is electrically rewritable. The gain and offset of the adjustmentamplifier 26 a are adjusted by rewriting values stored in thenonvolatile memory. With this configuration, the variation of output ofthe adjustment amplifier 26 a due to temperature change is cancelled.

<Filter>

The filter 24 has a resistor 24 a and a capacitor 24 b. As shown in FIG.7, a power source wiring 20 c, a first output wiring 20 d, a secondoutput wiring 20 e, and a ground wiring 20 f, as wiring patterns, areformed on the wiring board 20.

The ASIC 23 of the first sensing unit 21 is connected to the powersource wiring 20 c, the first output wiring 20 d, and the ground wiring20 f, respectively. An output terminal of the adjustment amplifier 26 aof the ASIC 23 of the first sensing unit 21 is connected to the firstoutput wiring 20 d.

The resistor 24 a of the filter 24 of the first sensing unit 21 isprovided on the first output wiring 20 d. The capacitor 24 b connectsthe first output wiring 20 d and the ground wiring 20 f. With thisconfiguration, the filter 24 of the first sensing unit 21 forms alow-pass filter with the resistor 24 a and the capacitor 24 b. An outputfrom the ASIC 23 of the first sensing unit 21 is provided via thelow-pass filter to the battery ECU 801. With this configuration, anoutput of the first sensing unit 21, from which high-frequency noise iseliminated, is provided to the battery ECU 801.

The ASIC 23 of the second sensing unit 22 is connected to the powersource wiring 20 c, the second output wiring 20 e, and the ground wiring20 f, respectively. The output terminal of the adjustment amplifier 26 aof the ASIC 23 of the first sensing unit 21 is connected to the secondoutput wiring 20 e.

The resistor 24 a of the filter 24 of the second sensing unit 22 isprovided on the second output wiring 20 e. The capacitor 24 b connectsthe second output wiring 20 e and the ground wiring 20 f. With thisconfiguration, the filter 24 of the second sensing unit 22 forms alow-pass filter with the resistor 24 a and the capacitor 24 b. An outputfrom the ASIC 23 of the second sensing unit 22 is provided via thelow-pass filter to the battery ECU 801. An output of the second sensingunit 22, from which high-frequency noise is eliminated, is provided tothe battery ECU 801.

As described above, the first sensing unit 21 and the second sensingunit 22 of the present embodiment have the same configuration. Therespective magnetoelectric converters 25 of the first sensing unit 21and the second sensing unit 22 are aligned in the y direction. Asdescribed later, the magnetic field which permeates the respectivemagnetoelectric converter 25 of the first sensing unit 21 and themagnetic field which permeates the respective magnetoelectric converter25 of the second sensing unit 22 are the same.

Accordingly, the electric signal provided from the first sensing unit 21to the battery ECU 801 and the electric signal provided from the secondsensing unit 22 to the battery ECU 801 are the same. The battery ECU 801determines whether or not an abnormality occurs in one of the firstsensing unit 21 and the second sensing unit 22 by comparing the twoelectric signals provided. In this manner, the first current sensor 11according to the preset embodiment has redundancy.

Note that the above-described shunt resistor 25 e may be provided in theresin section 28, or may be provided outside of the resin section 28.When the shunt resistor 25 e is provided outside of the resin section28, the shunt resistor 25 e is mounted on the wiring board 20. Then theshunt resistor 25 e is externally attached to the ASIC 23.

Further, as long as at least one of these four resistors is amagnetoresistive effect element, the respective four resistors formingthe full bridge circuit are not necessarily magnetoresistive effectelements. In place of the full bridge circuit, only one half bridgecircuit may be formed.

When the above-described redundancy is not required, as the firstcurrent sensor 11, a configuration having one of the first sensing unit21 and the second sensing unit 22 may be employed.

<Electrical-Conduction Bus Bar>

The electrical-conduction bus bar 30 is made of a conductive materialsuch as copper, brass, or aluminum. The electrical-conduction bus bar 30may be manufactured by the following methods, for example. Theelectrical-conduction bus bar 30 may be manufactured by press-working aflat plate. The electrical-conduction bus bar 30 may be manufactured byintegrally joining multiple flat plates. The electrical-conduction busbar 30 may be manufactured by welding multiple flat plates. Theelectrical-conduction bus bar 30 may be manufactured by pouring amolten-state conductive material into a mold. The manufacturing methodof the electrical-conduction bus bar 30 is not particularly limited.

As shown in FIG. 8, the electrical-conduction bus bar 30 has a thin flatshape having the thickness in the z direction. In theelectrical-conduction bus bar 30, a front surface 30 a and a rearsurface 30 b on the rear side of the front surface 30 a, respectively,face in the z direction. In FIG. 8, (a) shows a top view of theelectrical-conduction bus bar; and (b) shows a side view of theelectrical-conduction bus bar.

The electrical-conduction bus bar 30 extends in the y direction. Asmarked off with two broken lines in FIG. 8, the electrical-conductionbus bar 30 has a covered part 31 covered with the sensor housing 50, andfirst exposed part 32 and second exposed part 33 exposed from the sensorhousing 50. The first exposed part 32 and the second exposed part 33 arealigned via the covered part 31 in the y direction. The first exposedpart 32 and the second exposed part 33 are connected integrally via thecovered part 31.

As shown in (b) of FIG. 8, the respective dimensions (thicknesses) ofthe covered part 31, the first exposed part 32, and the second exposedpart 33 in the z direction are equal to each other. That is, respectivedistances in the z direction between the front surfaces 30 a and therear surfaces 30 b of the covered part 31, the first exposed part 32,and the second exposed part 33, are equal to each other.

A bolt hole 30 c for electrical and mechanical connection via a bolt tothe energization bus bar 307 is formed in each of the first exposed part32 and the second exposed part 33. The bolt hole 30 c passes througheach of the first exposed part 32 and the second exposed part 33 fromthe front surface 30 a to the rear surface 30 b.

As described above, the energization bus bar 307 is divided into thepart adjacent to the reactor 313 and the part adjacent to the high sideswitch 311. An attachment hole corresponding to the bolt hole 30 c isformed respectively in the part adjacent to the reactor 313 and in thepart adjacent to the high side switch 311 of the energization bus bar307.

The attachment hole of the energization bus bar 307 in the part adjacentto the reactor 313 and the bolt hole 30 c of the first exposed part 32are aligned in the z direction. The attachment hole of the energizationbus bar 307 in the part adjacent to the high side switch 311 and thebolt hole 30 c of the second exposed part 33 are aligned in the zdirection. In this status, a bolt shaft is inserted through the bolthole 30 c and the attachment hole. Then a nut is fastened from the endof the bolt shaft toward a bolt head. The energization bus bar 307 andthe electrical-conduction bus bar 30 are held between the bolt head andthe nut. With this configuration, the energization bus bar 307 and theelectrical-conduction bus bar 30 are brought into contact, and theenergization bus bar 307 and the electrical-conduction bus bar 30 areelectrically and mechanically connected to each other. As describedabove, in the energization bus bar 307, the divided part adjacent to thereactor 313 and the divided part adjacent to the high side switch 311are bridged with the electrical-conduction bus bar 30. A common currentflows through the energization bus bar 307 and the electrical-conductionbus bar 30.

As shown in (a) of FIG. 8, the covered part 31 has a narrow part 31 a atwhich the dimension in the x direction is locally short. In the narrowpart 31 a of the present embodiment, the dimension in the x direction isreduced in stepwise. In the narrow part 31 a, the dimension in the xdirection is reduced in two steps, from the first exposed part 32 sideof the covered part 31 toward a center point CP of the covered part 31in they direction. Similarly, in the narrow part 31 a, the dimension inthe x direction is reduced in two steps, from the second exposed part 33side of the covered part 31 toward the center point CP of the coveredpart 31 in the y direction. Note that the dimension of the narrow part31 a in the x direction may be reduced in more steps, or may becontinuously reduced.

The above-described center point CP is equivalent to the center ofgravity of the covered part 31. The covered part 31 and the narrow part31 a are in a line-symmetrical shape with a center line passing throughthe center point CP in the z direction as a symmetry axis AS.

In the narrow part 31 a, the dimension in the x direction is shorterthan that of the first exposed part 32 and the second exposed part 33.The density of a current flowing through the narrow part 31 a is higherthan the density of a current flowing through the first exposed part 32and the second exposed part 33. As a result, the intensity of a measuredmagnetic field to be measured, caused by the current flowing through thenarrow part 31 a is high.

As indicated with the magnetoelectric converter 25 in the first sensingunit 21 and the magnetoelectric converter 25 in the second sensing unit22, schematically surrounded with broken lines respectively, in (a) and(b) of FIG. 8, the first sensing unit 21 and the second sensing unit 22are each arranged to be opposed to and to be spaced from the narrow part31 a in the z direction. Accordingly, the high-intensity measuredmagnetic field, caused by the current flowing through the narrow part 31a, permeates the first sensing unit 21 and the second sensing unit 22respectively.

As described above, the electrical-conduction bus bar 30 extends in they direction. In the electrical-conduction bus bar 30, the current flowsin the y direction. A measured magnetic field in accordance withAmpere's law is generated in a circumferential direction about the ydirection by the flow of the current in the y direction. The measuredmagnetic field flows in a ring shape about the electrical-conduction busbar 30 in a plane defined by the x direction and the z direction. Thefirst sensing unit 21 and the second sensing unit 22 each detect acomponent of the measured magnetic field along the x direction.

As indicated with a broken line in FIG. 8, the respectivemagnetoelectric converters 25 of the first sensing unit 21 and thesecond sensing unit 22 are aligned in the y direction. The twomagnetoelectric converters 25 are symmetrically arranged with respect tothe symmetry axis AS. The positions of the two magnetoelectricconverters 25 in the x direction and the position of the symmetry axisAS (center point CP) in the x direction are the same. Accordingly, thetwo magnetoelectric converters 25 are aligned via the center point CP inthe y direction.

Further, the distances between the two magnetoelectric converters 25 andthe covered part 31 in the z direction are the same. As described above,the covered part 31 and the narrow part 31 a are in a line-symmetricalshape with respect to the symmetry axis AS. As described above, measuredmagnetic fields having equivalent x-direction components permeate thetwo magnetoelectric converters 25.

Note that the electrical-conduction bus bar 30 of the present embodimentis produced by press-working a conductive flat plate. In the pressworking, the flat plate is placed on a die, a puncher is brought to beclose to the die to apply a tensile force to the flat plate. With thiswork, the flat plate is divided into the electrical-conduction bus bar30 and chips, thus the electrical-conduction bus bar 30 is produced.

When the electrical-conduction bus bar 30 is produced by theabove-described press working, a shear plane is formed in theelectrical-conduction bus bar 30. A sag occurs in the shear plane on theside of a surface of the electrical-conduction bus bar 30, which isbrought into contact with the puncher first. With this sag, there is afear of perpendicularity impairment of the shear plane. As a result, thedistribution of the measured magnetic field caused by the currentflowing through the electrical-conduction bus bar 30 may be deviatedfrom the design.

In the present embodiment, the electrical-conduction bus bar 30 isarranged such that, not the surface that is brought into contact withthe puncher first, but a surface that is lastly separated with thepuncher is adjacent to the wiring board 20. That is, the surface that isfirstly brought into contact with the puncher is the rear surface 30 b,and the surface that is lastly separated from the puncher is the frontsurface 30 a. The shear plane corresponds to a side surface between thefront surface 30 a and the rear surface 30 b. Accordingly, theperpendicularity impairment on the front surface 30 a side in the sidesurface of the electrical-conduction bus bar 30 is suppressed. The frontsurface 30 a of the electrical-conduction bus bar 30 opposes the wiringboard 20. With this configuration, the deviation of the distribution ofthe measured magnetic field which permeates the first sensing unit 21and the second sensing unit 22 mounted on the wiring board 20 issuppressed.

Note that when the electrical-conduction bus bar 30 is produced by pressworking as described above, it is necessary to determine whether or nota sag has occurred on any of the front surface 30 a side and the rearsurface 30 b side in the side surface. For the purpose of the abovedetermination, a notch 33 a as a mark is formed in the second exposedpart 33 of the electrical-conduction bus bar 30. The notch 33 a of thepresent embodiment has a semicircular shape.

<Shield>

As described above, the shield 40 has the first shield 41 and the secondshield 42. As shown in FIG. 9 and FIG. 10, the first shield 41 and thesecond shield 42 each have a thin plate shape having the thickness inthe z direction. In the first shield 41, one surface 41 a having alargest area and a rear surface 41 b on the rear of the one surface 41 aface in the z direction respectively. In the second shield 42, onesurface 42 a having a largest area and a rear surface 42 b on the rearof the widest surface 42 a face in the z direction respectively.

As shown in FIG. 2 and FIG. 3, the first shield 41 and the second shield42 are provided, in a state where the one surface 41 a and the onesurface 42 a oppose each other in the z direction, in the sensor housing50. The rear surface 41 b of the first shield 41 and the rear surface 42b of the second shield 42 are exposed to the outside of the sensorhousing 50 respectively. The rear surface 41 b and the rear surface 42 beach form a part of an outer-most surface of the first current sensor11.

In FIG. 9, (a) shows a top view of the first shield; and (b) shows abottom view of the first shield. In FIG. 10, (a) shows a top view of thesecond shield; and (b) shows a bottom view of the second shield.

The first shield 41 and the second shield 42 may be produced bypress-joining multiple flat plates made of a soft magnetic material withhigh magnetic permeability such as permalloy. Otherwise, the firstshield 41 and the second shield 42 may be produced by press-extendingmagnetic steel.

The first shield 41 and the second shield 42 of the present embodimentare each produced by press-joining multiple flat plates made of a softmagnetic material. Each of the multiple flat plates is formed with fourprotrusions which protrude from a main surface toward a rear surface. Incorrespondence with the protrusions, each of the multiple flat plates isformed with four recesses which are recessed from the rear surfacetoward the main surface. The multiple flat plates are respectivelyarranged such that the main surface and the rear surface oppose to eachother. Further, the multiple flat plates are laminated such that theprotrusions of one of two opposing flat plates are received in therecesses of the other of the two opposing flat plates. In this laminatedstate, the multiple flat plates are press-joined. With thisconfiguration, the first shield 41 and the second shield 42 areproduced.

Note that, in the case where the first shield 41 and the second shield42 are produced by press-extending magnetic steel, the direction inwhich the magnetic steel is extended with the press-extension is, forexample, defined in the x direction. In this case, the atomicarrangement (crystal) of the magnetic steel is aligned in the xdirection. As a result, the magnetic permeability in the x direction ishigher than the magnetic permeability in the y direction. In thismanner, it is possible to provide the magnetic permeability of theshield with anisotropy by specifying the extending direction of themagnetic steel.

<First Shield>

As shown in FIG. 9, the planar shape of the first shield 41 is arectangular shape with the x direction as a longitudinal direction.Notches 41 c are formed at four corners of the first shield 41 of thepresent embodiment. In FIG. 9, to clarify the border between the centerof the first shield 41 and the opposite ends of the first shield 41 inthe y direction, two broken lines extending in the x direction are givento the first shield 41. In the following description, the center of thefirst shield 41 in the y direction is indicated as a first center part41 d. The opposite ends of the first shield 41 in the y direction areindicated as a first opposite end part 41 e. The first center part 41 dis positioned between the two ends of the first opposite end part 41 ein the y direction.

As clearly indicated with the broken lines, the first opposite end part41 e has the length in the x direction shorter than that of the firstcenter part 41 d. In the first opposite end part 41 e, the magneticpermeability in the x direction is thus lower than that in the firstcenter part 41 d. The magnetic field hardly enters the first oppositeend part 41 e. Accordingly, the permeation of the magnetic field, viaportions (parallel portions) of the first center part 41 d directlyconnected to the first opposite end part 41 e and aligned in the ydirection, from one of the two ends of the first opposite end part 41 eto the other end, is suppressed. The magnetic field hardly permeates theparallel portions of the first center part 41 d. As a result, theparallel portions of the first center part 41 d are hardly magneticallysaturated.

The parallel portions of the first center part 41 d, at which themagnetic saturation is suppressed, are aligned with the first sensingunit 21 and the second sensing unit 22 mounted on the wiring board 20 inthe z direction. The respective magnetoelectric converters 25 of thefirst sensing unit 21 and the second sensing unit 22 are positionedbetween the first center part 41 d and the narrow part 31 a.

<Second Shield>

As shown in FIG. 10, the planar shape of the second shield 42 is arectangular shape with the x direction as a longitudinal direction. InFIG. 10, to clarify the border between the center of the second shield42 and the opposite ends of the second shield 42 in the y direction, twobroken lines extending in the x direction are given to the second shield42. In the following description, the center of the second shield 42 inthe y direction is indicated as a second center part 42 d. The oppositeends of the second shield 42 are indicated as a second opposite end part42 e. The second center part 42 d is positioned between the two ends ofthe second opposite end part 42 e in the y direction.

The second shield 42 has two sides 42 f aligned in the x direction. Eachof the two sides 42 f is formed with an extending part 42 c extending inthe z direction in an area adjacent to the second center part 42 d. Thetwo extending parts 42 c extend in a direction from the rear surface 42b toward the one surface 42 a in the z direction. The extending part 42c has a rectangular parallelepiped shape with the y direction as alongitudinal direction. The extending part 42 c is formed, uponproduction of the second shield 42 as described above, after thepress-joining of the multiple flat plates made of a soft magneticmaterial, by bending the joined flat plates.

As described above, the first shield 41 and the second shield 42 areprovided, in a state where the one surface 41 a of the first shield 41and the one surface 42 a of the second shield 42 are opposed to eachother in the z direction, in the sensor housing 50. In this state wherethe first shield 41 and the second shield 42 are provided in the sensorhousing 50, the extending part 42 c extends toward the first shield 41.An end surface of the extending part 42 c and the one surface 41 a ofthe first center part 41 d of the first shield 41 are opposed to eachother in the z direction.

With this configuration, the clearance between the first center part 41d of the first shield 41 and the extending part 42 c of the secondshield 42 in the z direction is shorter than the clearance between theone surface 41 a of the first shield 41 and the one surface 42 a of thesecond shield 42 in the z direction. Accordingly, the magnetic fieldentered the first shield 41 easily permeates the second shield 42 viathe extending part 42 c.

As described above, the extending part 42 c extends from the side 42 fin the area adjacent to the second center part 42 d in the z direction.The extending part 42 c is not formed on the side 42 f in the areaadjacent to the second opposite end part 42 e. Therefore, the magneticfield entered the first shield 41 easily permeates the second centerpart 42 d of the second shield 42 via the extending part 42 c.

The second center part 42 d is opposed to the first sensing unit 21 andthe second sensing unit 22 mounted on the wiring board 20 in the zdirection. The magnetoelectric converters 25 and the narrow parts 31 aof the first sensing unit 21 and the second sensing unit 22 arepositioned between the first center part 41 d and the second center part42 d.

Further, the positions of the magnetoelectric converters 25 in the xdirection are between the two extending parts 42 c of the respective twosides 42 f. When external noise along the x direction attempts topermeate a region between the one surface 41 a of the first shield 41and the one surface 42 a of the second shield 42 in which themagnetoelectric converters 25 are positioned, the external noiseattempts to enter not the magnetoelectric converters 25 but theextending parts 42 c. In the extending parts 42 c, the external noisebents its permeation direction so as to permeate through the secondshield 42. As a result, permeation of the external noise through themagnetoelectric converters 25 is suppressed.

<Sensor Housing>

As shown in FIG. 3 and FIG. 11, the electrical-conduction bus bar 30 andthe connection terminal 60 are insert-molded in the sensor housing 50.The wiring board 20 and the shield 40 are provided in the sensor housing50. The electrical-conduction bus bar 30, the wiring board 20, and theshield 40 are aligned, away from each other, in the z direction. In FIG.11, (a) shows a top view of the sensor housing; and (b) shows a bottomview of the sensor housing.

As shown in FIG. 5 and FIG. 11, the sensor housing 50 has a base 51,insulating parts 52, a first surrounding part 53, a second surroundingpart 54, and a connector part 55.

The base 51 has a rectangular parallelepiped shape with the x directionas a longitudinal direction. The base 51 has six surfaces. The base 51has a left surface 51 a and a right surface 51 b facing in the ydirection. The base 51 has an upper surface 51 c and a lower surface 51d facing in the x direction. The base 51 has an upper end surface 51 eand a lower end surface 51 f facing in the z direction.

As shown in (a) and (c) of FIG. 5, the insulating parts 52 are formed ina part of the left surface 51 a and a part of the right surface 51 b inthe base 51, respectively. The two insulating parts 52 extend, away fromthe base 51, in the y direction. The two insulating parts 52 are alignedvia the base 51 in the y direction. The covered part 31 of theelectrical-conduction bus bar 30 is covered respectively with the twoinsulating parts 52 and the base 51.

In a broad way, portions of the covered part 31 adjacent to the firstexposed part 32 and the second exposed part 33 are covered with the twoinsulating parts 52. The narrow part 31 a of the covered part 31 iscovered with the base 51. The narrow part 31 a is positioned between theupper end surface 51 e and the lower end surface 51 f of the base 51 inthe z direction. An insulating resin material forming the base 51 ispositioned between the narrow part 31 a and the upper end surface 51 eand between the narrow part 31 a and the lower end surface 51 frespectively.

As shown in (a) of FIG. 11, the first surrounding part 53 is formed onthe upper end surface 51 e of the base 51. The first surrounding part 53has a left wall 53 a and a right wall 53 b aligned in the y direction.The first surrounding part 53 has an upper wall 53 c and a lower wall 53d aligned in the x direction.

These walls forming the first surrounding part 53 are formed along theedge of the upper end surface 51 e. In a circumferential direction aboutthe z direction, the left wall 53 a, the upper wall 53 c, the right wall53 b, and the lower wall 53 d are connected in sequence. With thisconfiguration, the first surrounding part 53 has a ring shape opened inthe z direction. The first surrounding part 53 surrounds the upper endsurface 51 e. The wiring board 20 and the first shield 41 are providedin first storage space provided by the first surrounding part 53 and theupper end surface 51 e.

As shown in (b) of FIG. 11, the second surrounding part 54 is formed onthe lower end surface 51 f of the base 51. The second surrounding part54 has a left wall 54 a and a right wall 54 b aligned in the ydirection. The second surrounding part 54 has an upper wall 54 c and alower wall 54 d aligned in the x direction.

These walls forming the second surrounding part 54 are formed around theabove-described part of the base 51 aligned with the narrow part 31 a inthe z direction on the lower end surface 51 f. In the circumferentialdirection about the z direction, the left wall 54 a, the upper wall 54c, the right wall 54 b, and the lower wall 54 d are connected insequence. With this configuration, the second surrounding part 54 has aring shape opened in the z direction. The second surrounding part 54surrounds a part of the lower end surface 51 f. The second shield 42 isprovided in second storage space provided by the second surrounding part54 and the lower end surface 51 f.

In the second storage space, the size of a plane orthogonal to the zdirection is smaller than that of the first storage space. The secondstorage space is aligned with a part of the first storage space in the zdirection. A part of the first storage space, which is not aligned withthe second storage space in the z direction, is aligned with theconnector part 55 in the z direction.

As shown in (b) of FIG. 5 and (b) of FIG. 11, the connector part 55 isformed on the lower end surface 51 f of the base 51. The connector part55 extends, away from a part of the lower end surface 51 f notsurrounded with the second surrounding part 54 (non-surrounded part), inthe z direction. The connector part 55 forms a part of the lower wall 54d.

The connector part 55 has a pillar part 55 a extending from the lowerend surface 51 f in the z direction, and a surrounding part 55 csurrounding an apical surface 55 b of the pillar part 55 a in thecircumferential direction about the z direction. The connection terminal60 extends in the z direction. The connection terminal 60 is coveredrespectively with the pillar part 55 a and a part of the base 51 alignedwith the pillar part 55 a in the z direction.

One end of the connection terminal 60 is exposed from the apical surface55 b to the outside of the pillar part 55 a. The periphery of the oneend of the connection terminal 60 exposed from the apical surface 55 bis surrounded by the above-described surrounding part 55 c. With thisconfiguration, the surrounding part 55 c and the one end of theconnection terminal 60 form a connector. A connector of a wire harnessor the like is connected to the connector.

The other end of the connection terminal 60 is exposed from the upperend surface 51 e to the outside of the base 51. The other end of theconnection terminal 60 is provided in the above-described first storagespace. The connection terminal 60 is away from the part of theelectrical-conduction bus bar 30 covered with the base 51 (narrow part31 a) in the x direction. The other end of the connection terminal 60 ispositioned adjacent to the lower wall 53 d in the x direction. Thenarrow part 31 a is positioned adjacent to the upper wall 53 c. Theinsulating resin material forming the base 51 is positioned between thepart of the connection terminal 60 and the part of the narrow part 31 arespectively insert-molded in the sensor housing 50.

As described above, the direct current inputted to or outputted from thebattery 200 flows through the electrical-conduction bus bar 30. In theconnection terminal 60, an electric signal with a smaller current amountthan the direct current flows between the wiring board 20 and thebattery ECU 801. When the creepage distance between theelectrical-conduction bus bar 30 and the connection terminal 60 isshort, there is a fear of short-circuit due to conduction between theelectrical-conduction bus bar 30 and the connection terminal 60.

A rib 52 a for suppressing such inconvenience is formed in theinsulating part 52. The rib 52 a protrudes from the insulating part 52in the z direction. The rib 52 a extends in the x direction. The lengthof the rib 52 a in the x direction is longer than the respective lengthsof the first exposed part 32 and the second exposed part 33 in the xdirection.

The rib 52 a is positioned between each of the first exposed part 32 andthe second exposed part 33 of the electrical-conduction bus bar 30,which are positioned outside of the insulating part 52, and the otherend of the connection terminal 60, which is exposed from the upper endsurface 51 e to the outside. With the ribs 52 a, the creepage distancebetween the electrical-conduction bus bar 30 and the connection terminal60 on the surface of the sensor housing 50 is elongated. With thisconfiguration, the short circuit between the electrical-conduction busbar 30 and the connection terminal 60 is suppressed.

Further, the ribs 52 a are positioned, respectively, between the firstexposed part 32 and the second exposed part 33, and the first shield 41and the second shield 42. With this configuration, short circuit betweenthe electrical-conduction bus bar 30 and the shield 40 is alsosuppressed.

It is possible to reduce the length of the insulating part 52 in the ydirection by the extension of the creepage distance with the ribs 52 a.The length of the insulating part 52 in the y direction is reduced byabout 85%. With this configuration, an increase of the physicalconstitution of the first current sensor 11 is suppressed.

<Wiring Board Fixing Form to Sensor Housing>

As shown in (a) of FIG. 11 and (a) of FIG. 12, a board support pin 56 aand a board adhesion pin 56 b locally extending in the z direction areformed on the upper end surface 51 e of the base 51. Multiple boardsupport pins 56 a and board adhesion pins 56 b are formed on the upperend surface 51 e. In FIG. 12, (a) shows a perspective view of the sensorhousing; and (b) shows a perspective view of the sensor housing in whichthe wiring board is provided. In FIG. 12, for explanation of these pins,a part of reference numerals is omitted.

The multiple board support pins 56 a each have an apical surface 56 cfacing in the z direction. The positions of the multiple apical surfaces56 c in the z direction are equal to each other. Similarly, the multipleboard adhesion pins 56 b each have an apical surface 56 d facing in thez direction. The positions of the multiple apical surfaces 56 d in the zdirection are equal to each other.

As shown in FIG. 13, the length between the apical surface 56 c of theboard support pin 56 a and the upper end surface 51 e in the z directionis defined as L1. The length between the apical surface 56 d of theboard adhesion pin 56 b and the upper end surface 51 e in the zdirection is defined as L2. As clearly indicated in the figure, thelength L1 is longer than the length L2.

Therefore, the apical surface 56 c of the board support pin 56 a is awayfrom the upper end surface 51 e, further than the apical surface 56 d ofthe board adhesion pin 56 b, in the z direction. The wiring board 20 ismounted, in a state where the opposing surface 20 a is in contact withthe apical surfaces 56 c of the board support pins 56 a, in the sensorhousing 50. The board support pin 56 a corresponds to a board supportpart. The apical surface 56 c corresponds to a support surface.

In the state where the wiring board 20 is mounted on the apical surfaces56 c of the board support pins 56 a, the opposing surface 20 a of thewiring board 20 is spaced from the apical surfaces 56 d of the boardadhesion pins 56 b in z direction. A board adhesive 56 e for adhesionfixing of the wiring board 20 and the board adhesion pin 56 b isprovided between the wiring board 20 and the board adhesion pin 56 b.The board adhesion pin 56 b corresponds to a board bonding member. Theapical surface 56 d corresponds to a mounting surface.

Upon adhesion fixing of the wiring board 20 and the sensor housing 50with the board adhesive 56 e, the temperature of the board adhesive 56 eis set to be higher than the temperature of an environment where thefirst current sensor 11 is provided. In this case, the temperature ofthe board adhesive 56 e may be set to about 150° C., for example. Atthis temperature, the board adhesive 56 e has fluidity. As the boardadhesive 56 e, a silicone adhesive may be employed.

The board adhesive 56 e having fluidity at about 150° C. is applied tothe apical surfaces 56 d of the board adhesion pins 56 b. Then, thewiring board 20 is placed in the sensor housing 50 so that the apicalsurfaces 56 c of the board support pins 56 a and the board adhesive 56 eare brought into contact with the opposing surface 20 a of the wiringboard 20. Thereafter, the board adhesive 56 e is cooled down to a roomtemperature to be solidified.

At the temperature of the environment where the first current sensor 11is provided, a residual stress condensing to its own center occurs tothe board adhesive 56 e. The wiring board 20 and the board adhesion pin56 b are brought closer to each other with the residual stress. Thecontact state between the opposing surface 20 a of the wiring board 20and the apical surfaces 56 c of the board support pins 56 a ismaintained.

As a result, misalignment of the wiring board 20 with respect to thesensor housing 50 does not depend on shape variation of the boardadhesive 56 e having fluidity upon adhesion fixing any longer. Themisalignment of the wiring board 20 with respect to the sensor housing50 is caused by a manufacturing error of the sensor housing 50. In otherwords, the misalignment of the wiring board 20 with respect to theelectrical-conduction bus bar 30 insert-molded in the sensor housing 50depends on the manufacturing error of the sensor housing 50.

In the present embodiment, three board support pins 56 a are formed onthe upper end surface 51 e. Two of the three board support pins 56 a arealigned, away from each other, in the y direction. The remaining oneboard support pin 56 a is away from a middle point between the two boardsupport pins 56 a aligned in the y direction, in the x direction. Theapical surfaces 56 c of the three board support pins 56 a form apexes ofan isosceles triangle. The narrow part 31 a of the electrical-conductionbus bar 30 is positioned between the two board support pins 56 a alignedin the y direction and the remaining one board support pin 56 a.

In the present embodiment, three board adhesion pins 56 b are formed onthe upper end surface 51 e. Two of the three board adhesion pins 56 bare aligned, away from each other, in the y direction. The remaining oneboard adhesion pin 56 b is away from a middle point between the twoboard support pins 56 a aligned in the y direction, in the x direction.The apical surfaces 56 d of the three board adhesion pins 56 b formapexes of an isosceles triangle.

The other ends of the multiple connection terminals 60 are alignedbetween the two board support pins 56 a aligned in the y direction. Theremaining one board support pin 56 a is positioned in the middle pointbetween the two board adhesion pins 56 b aligned in the y direction.Accordingly, the remaining one board support pin 56 a is aligned withthe remaining one board adhesion pin 56 b in the x direction. The centerpoint CP of the narrow part 31 a is positioned between the remaining oneboard support pin 56 a and the remaining one board adhesion pin 56 b inthe x direction.

With the above-described configuration, the isosceles triangle formed byconnecting the apical surfaces 56 c of the three board support pins 56 aand the isosceles triangle formed by connecting the apical surfaces 56 dof the three board adhesion pins 56 b overlap each other in the zdirection. The center point CP of the narrow part 31 a is positioned inthe region provided by these two isosceles triangles overlapping in thez direction.

The wiring board 20 is provided in the sensor housing 50 to be opposedto the two isosceles triangles, respectively, in the z direction. In thewiring board 20, the connection between a part opposing to the twoisosceles triangles and the sensor housing 50 is more stable, because ofthe contact with the board support pins 56 a and the connection with theboard adhesion pins 56 b via the board adhesive 56 e, than theconnection between a part without opposing to the two isoscelestriangles and the sensor housing 50. The first sensing unit 21 and thesecond sensing unit 22 are mounted on the part of the wiring board 20with stable connection with the sensor housing 50.

In a state where the wiring board 20 is mounted on the board supportpins 56 a and fixed via the board adhesive 56 e to the board adhesionpins 56 b, the opposing surface 20 a of the wiring board 20 and theupper end surface 51 e of the base 51 are opposed to each other andspaced from each other in the z direction. If there is no manufacturingerror or the like, the clearance between the opposing surface 20 a andthe upper end surface 51 e is constant over the entire surface, and theopposing surface 20 a and the upper end surface 51 e are in parallelrelationship.

As described above, the narrow part 31 a of the electrical-conductionbus bar 30 is insert-molded in the base 51. If there is no manufacturingerror or the like, the clearance between the surface 30 a of the narrowpart 31 a and the upper end surface 51 e of the base 51 is constant overthe entire surface, and the surface 30 a of the narrow part 31 a and theupper end surface 51 e of the base 51 are in parallel relationship.

Because of the parallel relationship described as above, if there is nomanufacturing error or the like, the clearance between the opposingsurface 20 a of the wiring board 20 and the surface 30 a of the narrowpart 31 a is also constant over the entire surface, and the opposingsurface 20 a of the wiring board 20 and the surface 30 a of the narrowpart 31 a are in parallel relationship.

As described above, the wiring board 20 is formed by laminating multipleresin layers and metal layers in the z direction. Therefore, themanufacturing error of the thickness of the wiring board 20 in the zdirection is likely to be large. The manufacturing error of thethickness of the wiring board 20 in the z direction is about twice ofthe manufacturing error due to the position of the electrical-conductionbus bar 30 insert-molded in the sensor housing 50 in the z direction andthe arrangement error of the wiring board 20 in the z direction withrespect to the sensor housing 50.

In the wiring board 20, the first sensing unit 21 and the second sensingunit 22 are provided on the opposing surface 20 a, which opposes to theelectrical-conduction bus bar 30. Therefore, the distance between thefirst sensing unit 21 and the electrical-conduction bus bar 30 and thedistance between the second sensing unit 22 and theelectrical-conduction bus bar 30 in the z direction do not depend on thethickness of the wiring board 20 in the z direction. Thus, variations ofthe distance between the first sensing unit 21 and theelectrical-conduction bus bar 30 and the distance between the secondsensing unit 22 and the electrical-conduction bus bar 30 in the zdirection due to the manufacturing error of the thickness of the wiringboard 20 in the z direction are suppressed.

Note that the number of the board support pins 56 a and the number ofthe board adhesion pins 56 b are not limited to three. The number of theboard support pins 56 a may be four or more. The number of the boardadhesion pins 56 b may be one, two, four or more.

When three or more board support pins 56 a and three or more boardadhesion pins 56 b are provided, it is desirable to configure such thatthe polygon formed by connecting the apical surfaces 56 c of the threeor more board support pins 56 a and the polygon formed by connecting theapical surfaces 56 d of the three or more board adhesion pins 56 boverlap each other in the z direction. In this configuration, the firstsensing unit 21 and the second sensing unit 22 may be mounted in aregion of the wiring board 20 opposing to the two polygons in the zdirection. With this configuration, the misalignment of the firstsensing unit 21 and the misalignment of the second sensing unit 22respectively with respect to the sensor housing 50 are suppressed.

As the names of board support pin 56 a and board adhesion pin 56 bindicate, the example where these pins have pillar shapes extending inthe z direction has been shown. However, the shapes of these pins arenot limited to the pillar shapes. As long as the apical surface 56 c ofthe board support pin 56 a is away from the upper end surface 51 efurther than the apical surface 56 d of the board adhesion pin 56 b, theshape is not particularly limited.

<Fixing Form of First Shield to Sensor Housing>

As shown in (a) of FIG. 11 and (a) of FIG. 14, a shield support pin 57 aand a shield adhesion pin 57 b are formed on the upper end surface 51 eof the base 51 to locally extending in the z direction. Multiple shieldsupport pins 57 a and shield adhesion pins 57 b are formed on the upperend surface 51 e. In FIG. 14, (a) shows a perspective view of the sensorhousing provided with the wiring board; and (b) shows a perspective viewof the sensor housing provided with the wiring board and the shield. InFIG. 14, a part of reference numerals is omitted for explanation ofthese pins.

The multiple shield support pins 57 a each have an apical surface 57 cfacing in the z direction. The positions of the multiple apical surfaces57 c in the z direction are equal to each other. Similarly, the multipleshield adhesion pins 57 b each have an apical surface 57 d facing in thez direction. The positions of the apical surfaces 57 d in the zdirection are equal to each other.

As shown in FIG. 15, in the respective shield support pin 57 a andshield adhesion pin 57 b, the length in the z direction is longer thanthat of the board support pin 56 a. More specifically, in the respectiveshield support pin 57 a and shield adhesion pin 57 b, the length in thez direction is longer than that of the board support pin 56 a by anamount equal to or larger than the thickness of the wiring board 20. Asdescribed above, in the state where the wiring board 20 is mounted inthe sensor housing 50, the apical surface 57 c of the shield support pin57 a and the apical surface 57 d of the shield adhesion pin 57 b arerespectively further from the upper end surface 51 e than the rearsurface 20 b of the wiring board 20 in the z direction. Note that aconfiguration where the difference between the length of the shieldadhesion pin 57 b and the length of the board support pin 56 a in the zdirection is shorter than the thickness of the wiring board 20 in the zdirection may be employed.

As shown in FIG. 15, the length between the apical surface 57 c of theshield support pin 57 a and the upper end surface 51 e in the zdirection is L3. The length between the apical surface 57 d of theshield adhesion pin 57 b and the upper end surface 51 e in the zdirection is L4. As clearly indicated in the figure, the length L3 islonger than the length L4.

The apical surface 57 c of the shield support pin 57 a is away from theupper end surface 51 e further than the apical surface 57 d of theshield adhesion pin 57 b in the z direction. The first shield 41 ismounted in the sensor housing 50 in the state where the one surface 41 ais in contact with the apical surface 57 c of the shield support pin 57a. The shield support pin 57 a corresponds to a shield support part. Theapical surface 57 c corresponds to the contact surface.

In the state where the one surface 41 a of the first shield 41 ismounted on the apical surface 57 c of the shield support pin 57 a, theone surface 41 a of the first shield 41 and the apical surface 57 d ofthe shield adhesion pin 57 b are away from each other in the zdirection. The board adhesive 56 e for adhesion fixing is providedbetween the first shield 41 and the shield adhesion pin 57 b. The shieldadhesion pin 57 b corresponds to a shield adhesion part. The apicalsurface 57 d corresponds to the application surface.

Upon the adhesion fixing between the first shield 41 and the sensorhousing 50 with the shield adhesive 57 e, the temperature of the shieldadhesive 57 e is set to be higher than the temperature of theenvironment where the first current sensor 11 is provided. Thetemperature of the shield adhesive 57 e in this case may be set to about150° C., for example. At this temperature, the shield adhesive 57 e hasfluidity. As the shield adhesive 57 e, a silicone adhesive may beemployed.

The shield adhesive 57 e having fluidity at about 150° C. is applied tothe apical surface 57 d of the shield adhesion pin 57 b. Then, the firstshield 41 is placed in the sensor housing 50 so as to bring the apicalsurface 57 c of the shield support pin 57 a and the shield adhesive 57 erespectively into contact with the one surface 41 a of the first shield41. Thereafter, the shield adhesive 57 e is cooled down to the roomtemperature to be solidified.

Thus, in the shield adhesive 57 e, a residual stress condensing to itsown center occurs at the temperature of the environment where the firstcurrent sensor 11 is provided. The first shield 41 and the shieldadhesion pin 57 b are brought closer to each other with the residualstress. The contact state between the one surface 41 a of the firstshield 41 and the apical surface 57 c of the shield support pin 57 a ismaintained.

As a result, the misalignment of the first shield 41 with respect to thesensor housing 50 does not depend on the shape variation of the shieldadhesive 57 e having fluidity upon adhesion fixing any longer. Themisalignment of the first shield 41 with respect to the sensor housing50 is caused by the manufacturing error of the sensor housing 50. Inother words, the misalignment of the first shield 41 with respect to thewiring board 20 fixed to the sensor housing 50 depends on themanufacturing error of the sensor housing 50.

In the present embodiment, three shield support pins 57 a are formed onthe upper end surfaces 51 e. One of the three shield support pins 57 ais connected integrally with the left wall 53 a. One of the remainingtwo shield support pins 57 a is connected integrally with the right wall53 b. The remaining one shield support pin 57 a is connected integrallywith the upper wall 53 c. The apical surfaces 57 c of the three shieldsupport pins 57 a form apexes of a triangle.

The shield support pin 57 a connected integrally with the left wall 53 aand the shield support pin 57 a connected integrally with the right wall53 b are aligned in the y direction. The interval between the two shieldsupport pins 57 a and the shield support pin 57 a connected integrallywith the upper wall 53 c are away from each other in the x direction.The first sensing unit 21 and the second sensing unit 22 of the wiringboard 20 are positioned in the triangular region formed by connectingthe apical surfaces 57 c of the three shield support pins 57 a.

In the present embodiment, three shield adhesion pins 57 b are formed onthe upper end surface 51 e. One of the three shield adhesion pins 57 bis connected integrally with the left wall 53 a. One of the remainingtwo shield adhesion pins 57 b is connected integrally with the rightwall 53 b. The remaining one shield adhesion pin 57 b is connectedintegrally with the upper wall 53 c. The apical surfaces 57 d of thethree shield adhesion pins 57 b form apexes of a triangle.

The shield adhesion pin 57 b connected integrally with the left wall 53a, and the shield adhesion pin 57 b connected integrally with the rightwall 53 b, are aligned in the y direction. The interval between the twoshield adhesion pins 57 b and the shield adhesion pin 57 b connectedintegrally with the upper wall 53 c are away from each other in the xdirection. The triangular region formed by connecting the apicalsurfaces 57 d of the three shield adhesion pins 57 b is aligned with thefirst sensing unit 21 and the second sensing unit 22 in the z direction.

Further, one shield support pin 57 a and one shield adhesion pin 57 bare aligned with each other on each of the left wall 53 a and the rightwall 53 b. One shield support pin 57 a and one shield adhesion pin 57 bare aligned with each other on the upper wall 53 c. The triangle formedby connecting the apical surfaces 57 c of the three shield support pins57 a and the triangle formed by connecting the apical surfaces 57 d ofthe three shield adhesion pins 57 b overlap each other in the zdirection. The overlapping region of the triangles in the z directionand the center point CP of the narrow part 31 a are aligned in the zdirection.

The first shield 41 is provided in the sensor housing 50 so as to opposethe two triangles in the z direction. In the first shield 41, theconnection with the sensor housing 50 of the part opposing to the twotriangles is more stable, by the contact with the shield support pin 57a and the connection with the shield adhesion pin 57 b via the shieldadhesive 57 e, than that of the part without opposing to the twotriangles.

The part of the first shield 41 with stable connection to the sensorhousing 50 is aligned with both of the first sensing unit 21 and thesecond sensing unit 22 of the wiring board 20 in the z direction.Specifically, the first center part 41 d of the first shield 41 isaligned with each of the first sensing unit 21 and the second sensingunit 22 in the z direction.

In the state where the first shield 41 is mounted on the shield supportpin 57 a and fixed via the shield adhesive 57 e to the shield adhesionpin 57 b, the one surface 41 a of the first shield 41 and the rearsurface 20 b of the wiring board 20 are opposed to and away from eachother in the z direction. If there is no manufacturing error or thelike, the distance between the one surface 41 a and the rear surface 20b is constant over the entire surface, and the one surface 41 a and therear surface 20 b are in parallel relationship. Accordingly, thedistance between the opposing surface 20 a of the wiring board 20 andthe one surface 41 a of the first shield 41 is also constant over theentire surface, and the opposing surface 20 a of the wiring board 20 andthe one surface 41 a of the first shield 41 are in parallelrelationship.

Note that, as shown in FIG. 6 and (a) in FIG. 14, notches 20 g to allowthe above-described shield support pins 57 a and shield adhesion pins 57b respectively to pass through to positions above the wiring board 20are formed at ends the wiring board 20. Multiple through holes 20 h toallow the other ends of the connection terminals 60 to pass through areformed in the wiring board 20.

As shown in FIG. 6, the multiple through holes 20 h are aligned in the ydirection. In the wiring board 20, the part in which the multiplethrough holes 20 h are formed is aligned with the part on which thefirst sensing unit 21 and the second sensing unit 22 are mounted in thex direction. In the wiring board 20, a first notch 20 i to guide theposition of the wiring board 20 with respect to the sensor housing 50 inthe x direction when the wiring board 20 is mounted in the sensorhousing 50 is formed between the two parts aligned in the x direction.Further, in the wiring board 20, a second notch 20 j to guide theposition of the wiring board 20 with respect to the sensor housing 50 inthe y direction when the wiring board 20 is mounted in the sensorhousing 50 is formed in the part where the first sensing unit 21 and thesecond sensing unit 22 are mounted.

In correspondence with the above configuration, as shown in (a) of FIG.11 and (b) of FIG. 12, a first projection 53 e to be received in thefirst notch 20 i is formed on each of the left wall 53 a and the rightwall 53 b of the sensor housing 50. A second projection 53 f, which isto be opposed to the second notch 20 j in the y direction, is formed oneach of the left wall 53 a and the right wall 53 b. The first notch 20 iand the first projection 53 e have similar shapes and extend in the ydirection. The second notch 20 j and the second projection 53 f havesimilar shapes and extend in the x direction.

The number of the above-described shield support pins 57 a and thenumber of the shield adhesion pins 57 b are not limited to theabove-described example. The number of the shield support pins 57 a maybe four or more. The number of the shield adhesion pins 57 b may be one,two, four or more.

When three or more shield support pins 57 a and three or more shieldadhesion pins 57 b are employed, it is desirable to configure such thatthe polygon formed by connecting the apical surfaces 57 c of the threeor more shield support pins 57 a and the polygon formed by connectingthe apical surfaces 57 d of the three or more shield adhesion pins 57 boverlap each other in the z direction. In this configuration, the partof the first shield 41 opposing to the two polygons in the z directionmay be aligned with both of the first sensing unit 21 and the secondsensing unit 22 of the wiring board 20 in the z direction. In such acase, the misalignment of the first shield 41 with respect to the firstsensing unit 21 and the misalignment of the first shield 41 with respectto the second sensing unit 22 are suppressed.

As the names of shield support pin 57 a and shield adhesion pin 57 bindicate, the example where these pins have pillar shapes extending inthe z direction has been shown. However, the shapes of the pins are notlimited to the pillar shapes. As long as the apical surface 57 c of theshield support pin 57 a is away from the upper end surface 51 e furtherthan the apical surface 57 d of the shield adhesion pin 57 b, the shapeis not particularly limited.

<Fixing Form of Second Shield to Sensor Housing>

As shown in (b) of FIG. 11 and FIG. 15, multiple shield support pins 57a are formed also on the lower end surface 51 f of the base 51.

Differently from the first shield 41, the wiring board 20 is notprovided between the sensor housing 50 and the second shield 42.Therefore, in the shield support pin 57 a formed on the lower endsurface 51 f, the length in the z direction is shorter than that of theshield support pin 57 a formed on the upper end surface 51 e. Thepositions of the respective ends of the multiple board support pins 56 ain the z direction are equal to each other. The second shield 42 ismounted in the sensor housing 50 in the state where the one surface 42 ais in contact with the apical surface 57 c of the shield support pin 57a.

The one surface 42 a of the second shield 42, mounted on the apicalsurface 57 c of the shield support pin 57 a, is away from the lower endsurface 51 f in the z direction. The shield adhesive 57 e is providedbetween the second shield 42 and the lower end surface 51 f.

Upon adhesion fixing between the second shield 42 and the sensor housing50 with the shield adhesive 57 e, the temperature of the shield adhesive57 e is also set to be higher than the temperature of the environmentwhere the first current sensor 11 is provided.

The shield adhesive 57 e having fluidity is applied to the lower endsurface 51 f. Then, the second shield 42 is placed in the sensor housing50 so as to bring the apical surface 57 c of the shield support pin 57 aand the shield adhesive 57 e respectively into contact with the onesurface 42 a of the second shield 42. Thereafter, the shield adhesive 57e is cooled down to the room temperature to be solidified.

With this configuration, also in the shield adhesive 57 e provided onthe lower end surface 51 f, a residual stress condensing to its owncenter occurs at the temperature of the environment where the firstcurrent sensor 11 is provided. The second shield 42 and the shieldadhesion pin 57 b are brought closer to each other with the residualstress. The contact status between the one surface 42 a of the secondshield 42 and the apical surface 57 c of the shield support pin 57 a ismaintained.

As a result, the misalignment of the second shield 42 with respect tothe sensor housing 50 does not depend on the shape variation of theshield adhesive 57 e having fluidity upon the adhesion fixing anylonger. The misalignment of the second shield 42 with respect to thesensor housing 50 is caused by the manufacturing error of the sensorhousing 50. In other words, the misalignment of the second shield 42with respect to the wiring board 20 fixed to the sensor housing 50depends on the manufacturing error of the sensor housing 50.

In the present embodiment, four shield support pins 57 a are formed onthe lower end surface 51 f. The apical surfaces 57 c of the four shieldsupport pins 57 a form vertices of a rectangle. The rectangle formed byconnecting the apical surfaces 57 c of the four shield support pins 57 ais aligned with the center point CP of the narrow part 31 a in the zdirection. The shield adhesive 57 e is applied to a region opposing tothe rectangle in the lower end surface 51 f.

The second shield 42 is provided in the sensor housing 50 to be opposedto the above-described rectangle in the z direction. In the part of thesecond shield 42 opposing to the rectangle, the connection to the sensorhousing 50 is more stable by the contact with the shield support pin 57a and the connection via the shield adhesive 57 e to the lower endsurface 51 f, than the connection of the part without opposing to therectangle to the sensor housing 50.

The part of the second shield 42, with stable connection to the sensorhousing 50, is aligned with both of the first sensing unit 21 and thesecond sensing unit 22 of the wiring board 20 in the z direction.Specifically, the second center part 42 d of the second shield 42 isaligned respectively with the first sensing unit 21 and the secondsensing unit 22 in the z direction.

Note that the number of shield support pins 57 a formed on the lower endsurface 51 f is not limited to four. As long as the number of shieldsupport pins 57 a is equal to or larger than three, any number of shieldsupport pins 57 a may be employed.

When three or more shield support pins 57 a are provided, it may beconfigured such that a region of the second shield 42, opposing to thepolygon formed by connecting the apical surfaces 57 c of the three ormore shield support pins 57 a in the z direction, is alignedrespectively with the first sensing unit 21 and the second sensing unit22 in the z direction. With this configuration, the misalignment of thesecond shield 42 with respect to the first sensing unit 21 and themisalignment of the second shield 42 with respect to the second sensingunit 22 are suppressed.

As described above, the extending parts 42 c extending in the zdirection are formed on the two sides 42 f of the second shield 42aligned in the x direction. Two grooves 51 g for arranging the extendingparts 42 c are formed in the lower end surface 51 f.

As shown in (b) of FIG. 11 and in FIG. 13, the two grooves 51 g arealigned in the x direction between the upper wall 54 c and the lowerwall 54 d. The two grooves 51 g are each formed from the lower endsurface 51 f toward the upper end surface 51 e in the z direction. Apart of one of the two grooves 51 g is formed by the upper wall 54 c. Apart of the remaining one groove 51 g is formed by the lower wall 54 d.The covered part 31 is positioned between the two grooves 51 g.Accordingly, the covered part 31 is positioned between the two extendingparts 42 c of the second shield 42.

<Lengths of Support Pin and Adhesion Pin>

The upper end surface 51 e of the base 51 is divided into an exposedpart from which the other end of the connection terminal 60 expose and apart which covers the narrow part 31 a, which are aligned in the xdirection but with the above-described first projections 53 e in the ydirection as a boundary. In the upper end surface 51 e, the exposed partfrom which the other end of the connection terminal 60 expose ispositioned adjacent to the lower end surface 51 f than the part whichcovers the narrow part 31 a in the z direction. Accordingly, thedistance between the exposed part of the upper end surface 51 e fromwhich the other end of the connection terminal 60 expose and theopposing surface 20 a of the wiring board 20 in the z direction islonger than the distance between the part of the upper end surface 51 ewhich covers the narrow part 31 a and the opposing surface 20 a of thewiring board 20 in the z direction. The distance between the exposedpart of the upper end surface 51 e from which the other end of theconnection terminal 60 expose and the opposing surface 20 a of thewiring board 20 is provided so as to ensure a distance for insertion ofthe other end of the connection terminal 60 into the through hole 20 hof the wiring board 20.

In this manner, in the upper end surface 51 e, the position of theexposed part from which the other end of the connection terminal 60expose and the position of the part which covers the narrow part 31 aare different in the z direction. The board support pins 56 a are formedrespectively in these two parts. In the present embodiment, although theparts of the upper end surface 51 e are at different positions in the zdirection, the apical surfaces 56 c of the multiple board support pins56 a are at the same positions in the z direction. Thus, the lengths ofthe multiple board support pins 56 a in the z direction are different.

The lengths of the multiple board support pins 56 a in the z directionare not uniformly equal to the length L1 shown in FIG. 13. The length L1indicates the length of the board support pin 56 a formed on the part ofthe upper end surface 51 e which covers the narrow part 31 a in the zdirection. The length of the board support pin 56 a formed in theexposed part of the upper end surface 51 e from which the other end ofthe connection terminal 60 expose in the z direction is longer than thelength L1 by the difference in position of the divided two parts of theupper end surface 51 e in the z direction.

As described above, the length of the support pin in the z direction maydiffer in correspondence with the position of the surface where the pinis formed in the z direction as long as the positions of the respectiveapical surfaces 56 c of the multiple board support pins 56 a in the zdirection are the same. The configuration is true for the multipleshield support pins 57 a.

Note that, when the wiring board 20 is mounted in the sensor housing 50,the board adhesive 56 e having fluidity is applied to the apicalsurfaces 56 d of the board adhesion pins 56 b. The shape of the boardadhesive 56 e, having fluidity, is variable in the z direction.Accordingly, the positions of the apical surfaces 56 d of the multipleboard adhesion pins 56 b may be different. This is also true for themultiple shield adhesion pins 57 b.

<Second Current Sensor and Third Current Sensor>

Next, the second current sensor 12 will be described in detail. Notethat the configuration of the second current sensor 12 and theconfiguration of the third current sensor 13 are substantially the same.Accordingly, explanation of the third current sensor 13 will be omitted.

Further, the second current sensor 12 has constituent elements common tothe first current sensor 11. In the following description, explanationof the points same as those of the first current sensor 11 will beomitted, and the differences will be mainly described.

As described above, the second current sensor 12 is provided on thefirst energization bus bar 341 and the second energization bus bar 342.To detect the current flowing in the first energization bus bar 341 andthe current flowing in the second energization bus bar 342 respectively,the second current sensor 12 has two individual sensors 71 having afunction equivalent to the function of the first current sensor 11.Further, the second current sensor 12 has a wiring case 72 accommodatingthe two individual sensors 71.

One of the two individual sensors 71 detects the magnetic fieldgenerated from the alternating current which flows through the firstenergization bus bar 341. The other one of the two individual sensors 71detects the magnetic field generated from the alternating current whichflows through the second energization bus bar 342.

FIG. 16 shows the two individual sensors 71. The two individual sensors71 have the same shape. The structural differences between theindividual sensor 71 and the first current sensor 11 include theconnecting part in the electrical-conduction bus bar 30 with respect tothe energization bus bar, the shape of the connector part 55 whichcovers the connection terminal 60, and the like. That is, the structuraldifferences between the individual sensor 71 and the first currentsensor 11 include the shape of the first exposed part 32 and the secondexposed part 33 of the electrical-conduction bus bar 30, and eliminationof the surrounding part 55 c, and the like.

The individual sensor 71 and the first current sensor 11 have thestructural differences because the objects to which the individualsensor 71 and the first current sensor 11 are connected are difference.The first current sensor 11 is connected to the energization bus bar 307of the converter 310. The second current sensor 12 is connected to thefirst energization bus bar 341 and the second energization bus bar 342of the first inverter 320. Note that the internal structure of theindividual sensor 71 and the internal structure of the first currentsensor 11 are the same. Accordingly, the individual sensor 71 achievessimilar effects to those of the first current sensor 11.

The multiple individual sensors 71 are accommodated in the wiring case72 shown in FIG. 17. As shown in FIG. 18, the multiple individualsensors 71 can be accommodated collectively in the wiring case 72. Asshown in FIG. 19, the second current sensor 12 is configured byaccommodating the multiple individual sensors 71 in the wiring case 72.

Note that in the case of this configuration, the first shields 41 andthe second shields 42 of the respective individual sensors 71 arealternately aligned in the x direction. The magnetoelectric converter 25of the individual sensor 71 has sensing directions of the magnetic fieldin the z direction and in the y direction.

Further, six individual sensors 71 are accommodated in the wiring case72 shown in the previously shown FIG. 17 to FIG. 19 and the followingfigures. The number of the individual sensors 71 accommodated in thewiring case 72 is merely an example. As long as the wiring case 72 iscapable of accommodating at least two individual sensors 71, any numberof individual sensors 71 may be accommodated in the wiring case 72.

Further, a current sensor that detects a current in another in-vehicleequipment may be accommodated in the wiring case 72 of the secondcurrent sensor 12. Further, it is possible to employ a configurationwhere the second current sensor 12 and the third current sensor 13 sharea wiring case 72, and the individual sensors 71 of the second currentsensor 12 and the third current sensor 13 are accommodated in the samewiring case 72.

<Wiring Case>

As shown in FIG. 17, the wiring case 72 has an integrated housing 73, aterminal housing 74, and an energization terminal 75. The integratedhousing 73 and the terminal housing 74 are made of an insulating resinmaterial. The integrated housing 73 and the terminal housing 74 areintegrally connected to each other. As shown in FIG. 18 and FIG. 19,multiple individual sensors 71 are accommodated in the integratedhousing 73. Accordingly, the physical constitution of the integratedhousing 73 is larger than the physical constitution of the sensorhousing 50 of the individual sensor 71. Multiple energization terminals75 are insert-molded in the terminal housing 74. As shown in FIG. 20 toFIG. 23, one ends and the other ends of the multiple energizationterminals 75 are exposed to the outside of the terminal housing 74.

In FIG. 20, (a) shows a rear view of the wiring case; (b) shows a topview of the wiring case; and (c) shows a bottom view of the wiring case.In FIG. 21, (a) shows a left side view of the wiring case; (b) shows atop view of the wiring case; and (c) shows a right side view of thewiring case. Note that (b) of FIG. 20 and (b) of FIG. 21 show the samefigure.

In FIG. 22, (a) shows a front view of the second current sensor; (b)shows a top view of the second current sensor; and (c) shows a bottomview of the second current sensor. In FIG. 23, (a) shows a side view ofthe second current sensor; and (b) shows a top view of the secondcurrent sensor. Note that (b) of FIG. 22 and (b) of FIG. 23 show thesame figure.

As respectively shown in (c) of FIG. 20 and (c) of FIG. 22, the wiringcase 72 has an integrated wiring board 76. The one end of the connectionterminal 60 of the individual sensor 71 is connected to the integratedwiring board 76. One end of the energization terminal 75 is connected tothe integrated wiring board 76. With this configuration, the individualsensor 71 and the energization terminal 75 are electrically connected toeach other via the wiring pattern of the integrated wiring board 76. Theother end of the energization terminal 75 is electrically connected viaa wire harness or the like to the MG ECU 802. As described above, outputof the individual sensor 71 is transmitted via the integrated wiringboard 76, the energization terminal 75, and the wire harness, into theMG ECU 802. The integrated wiring board 76 and the energization terminal75 correspond to an input/output wiring.

As described above, the second current sensor 12 is provided on thefirst energization bus bar 341 and the second energization bus bar 342.These energization bus bars are respectively divided into a partadjacent to the first inverter 320 and a part adjacent to the firstmotor 400. The energization bus bar has a part to connect the firstinverter 320 to the second current sensor 12 and a part to connect thesecond current sensor 12 to the first motor 400.

In the energization bus bar of the present embodiment, the part toconnect the first inverter 320 to the second current sensor 12 isprovided by a conductive plate made of a metal material. The part of theenergization bus bar to connect the second current sensor 12 to thefirst motor 400 is provided by a wire. In the following description, thepart of the energization bus bar to connect the first inverter 320 tothe second current sensor 12 will be simply referred to as theconductive plate. The part of the energization bus bar to connect thesecond current sensor 12 to the first motor 400 will be simply referredto as the wire.

Note that the form of the energization bus bar is arbitrarily modifiedin correspondence with respective shapes of the inverter and the motor,and in correspondence with mounting form of the inverter and the motorin the vehicle and the like. Accordingly, the specific form of theenergization bus bar is not limited to the above-described example. Incorrespondence with form of the energization bus bar, the respectiveforms of the electrical-conduction bus bar 30 in the wiring case 72 andthe individual sensor 71 are arbitrarily modified. Especially, the formof the electrical-conduction bus bar 30 in the individual sensor 71 canbe modified only by changing the respective shapes of the first exposedpart 32 and the second exposed part 33. Accordingly, it is not necessaryto modify the internal shape of the individual sensor 71. With thisconfiguration, it is not necessary to change a production line of theindividual sensor 71.

As shown in FIG. 20 and FIG. 21, the integrated housing 73 has a bottomwall 77 and a peripheral wall 78. The bottom wall 77 faces in the zdirection. The planar shape of the bottom wall 77 is a rectangular shapewith the x direction as a longitudinal direction.

The peripheral wall 78 rises in the z direction from an inner bottomsurface 77 a of the bottom wall 77 facing in the z direction. Theperipheral wall 78 has a left wall 78 a and a right wall 78 b aligned inthe x direction. The peripheral wall 78 has an upper wall 78 c and alower wall 78 d aligned in the y direction. The left wall 78 a, theupper wall 78 c, the right wall 78 b, and the lower wall 78 d areconnected in sequence in the circumferential direction about the zdirection. With this configuration, the peripheral wall 78 forms acylindrical shape having an opening in the z direction. The multipleindividual sensors 71 can be housed in the storage space provided by thebottom wall 77 and the peripheral wall 78.

As shown in FIG. 18, the individual sensor 71 is inserted along the zdirection into the storage space of the integrated housing 73. As shownin FIG. 19, the multiple individual sensors 71 are aligned in the xdirection in the storage space.

Similarly to the first current sensor 11, the multiple individualsensors 71 each have the first shield 41 and the second shield 42. Thefirst shield 41 and the second shield 42 are opposed to and away fromeach other in the x direction. Accordingly, in the storage space, thefirst shields 41 and the second shields 42 of the multiple individualsensors are alternately aligned.

As shown in FIG. 16, the first exposed part 32 and the second exposedpart 33 extend in the y direction from the sensor housing 50 of theindividual sensor 71. The upper wall 78 c of the integrated housing 73is formed with slits 78 e for allowing the ends of the first exposedparts 32 of the sensor housings 50 of the individual sensors 71accommodated in the storage space to be placed outside of the storagespace. The slits 78 e are each formed along the z direction from theapical surface of the upper wall 78 c toward the bottom wall 77.

In the stats where the individual sensor 71 is accommodated in theintegrated housing 73, the end of the first exposed part 32 of theindividual sensor 71 is positioned via the slit 78 e on the outside ofthe storage space. The end of the first exposed part 32 is electricallyconnected to the above-described conductive plate by laser welding orthe like.

Further, a conductive terminal 79 is insert-molded in the bottom wall 77of the integrated housing 73. As shown in (b) of FIG. 20 and (b) of FIG.21, a part of the conductive terminal 79 is exposed from the innerbottom surface 77 a of the bottom wall 77.

In the state where the individual sensor 71 is accommodated in theintegrated housing 73, the second exposed part 33 of the individualsensor 71 is opposed to the part of the conductive terminal 79 exposedfrom the inner bottom surface 77 a. The second exposed part 33 and theconductive terminal 79 are electrically connected to each other by laserwelding or the like.

Further, the integrated housing 73 has a terminal block 80 to supportthe multiple conductive terminals 79. The terminal block 80 is formedintegrally with the lower wall 78 d adjacent to the bottom wall 77. Theterminal block 80 has a rectangular parallelepiped shape extending inthe x direction. The multiple conductive terminals 79 are insert-moldedalso in the terminal block 80. The multiple conductive terminals 79 arepartly exposed from the terminal block 80. The part of the conductiveterminal 79 exposed from the terminal block 80 extends away from theterminal block 80 in the z direction. The part of the conductiveterminal 79 exposed from the terminal block 80 opposes the lower wall 78d in the y direction. The parts of the multiple conductive terminals 79exposed from the terminal block 80 are aligned with each other acrossspaces in the x direction.

The part of the conductive terminal 79 exposed from the terminal block80 has a flat shape in which the thickness in the y direction is thin.The part of the conductive terminal 79 exposed from the terminal block80 has an energization surface 79 a facing in the y direction and itsrear surface 79 b. In the conductive terminal 79, a bolt hole 79 c isformed to pass through from the energization surface 79 a to the rearsurface 79 b in the y direction.

Further, the rear surface 79 b of the conductive terminal 79 is providedwith a nut 81 opened in the y direction. The opening of the nut 81 andthe opening of the bolt hole 79 c are aligned in the y direction.

A terminal of the wire is disposed on the energization surface 79 a ofthe conductive terminal 79. The terminal of the wire also has a bolthole penetrating in the y direction. In the terminal of the wire, thesurface on which the bolt hole is formed is opposed to the energizationsurface 79 a of the conductive terminal 79. In this state, a bolt shaft(not illustrated) is inserted through the bolt holes of the conductiveterminal 79 and the terminal of the wire. Then, the end of the boltshaft is fastened to the nut 81. The bolt is fastened to the nut 81 fromthe end of the bolt shaft toward a bolt head. The conductive terminal 79and the terminal of the wire are held between the bolt head and the nut81. With this configuration, the terminal of the wire and the conductiveterminal 79 are brought into contact and electrically and mechanicallyconnected to each other. As described above, the second exposed part 33of the individual sensor 71 and the wire terminal are electricallyconnected to each other via the conductive terminal 79.

The connection terminal 60 extends from the sensor housing 50 of theindividual sensor 71 in the z direction. An insertion hole for allowingthe one end of the connection terminal 60 to be placed on the outside ofthe storage space is formed in the bottom wall 77 of the integratedhousing 73. The insertion hole is formed to pass through from the innerbottom surface 77 a of the bottom wall 77 to an outer bottom surface 77b on the rear side of the inner bottom surface 77 a. The one end of theconnection terminal 60 protrudes, away from the outer bottom surface 77b via the insertion hole, to the outside of the storage space. Since theinsertion hole is a minute hole, it is not shown in the figure.

The terminal housing 74 is aligned with the integrated housing 73 in thex direction. The terminal housing 74 is connected integrally with theleft wall 78 a of the integrated housing 73. The terminal housing 74extends in the z direction. The terminal housing 74 has an upper surface74 a and a lower surface 74 b aligned in the z direction.

The multiple energization terminals 75 insert-molded in the terminalhousing 74 extend in the z direction. One end of the energizationterminal 75 projects from the lower surface 74 b of the terminal housing74. The other end of the energization terminal 75 projects from theupper surface 74 a of the terminal housing 74.

As shown in (a) and (c) of FIG. 20, the outer bottom surface 77 b of thebottom wall 77 of the integrated housing 73 and the lower surface 74 bof the terminal housing 74 continuous each other in the x direction andthe y direction. The integrated wiring board 76 is provided on the outerbottom surface 77 b and the lower surface 74 b, which are continuous toeach other.

The integrated wiring board 76 has a flat shape in which the thicknessin the z direction is thin. The integrated wiring board 76 has amounting surface 76 a facing in the z direction and a rear surface 76 b.The integrated wiring board 76 is fixed, in a state where the mountingsurface 76 a opposes respectively to the outer bottom surface 77 b andthe lower surface 74 b in the z direction, to the integrated housing 73and the terminal housing 74.

As described above, the one end of the energization terminal 75 projectsfrom the lower surface 74 b. The one end of the connection terminal 60projects from the outer bottom surface 77 b. On the other hand, a firstthrough hole 76 c is formed in the integrated wiring board 76 to receivethe one end of the energization terminal 75. A second through hole 76 dis formed in the integrated wiring board 76 to receive the one end ofthe connection terminal 60. The first through hole 76 c and the secondthrough hole 76 d penetrate the integrated wiring board 76 from themounting surface 76 a to the rear surface 76 b in the z direction.Further, a wiring pattern which electrically connects the first throughhole 76 c to the second through hole 76 d is formed on the integratedwiring board 76.

The integrated wiring board 76 is arranged on the outer bottom surface77 b and the lower surface 74 b such that the one end of theenergization terminal 75 is inserted into the first through hole 76 c.Then, the first through hole 76 c and the energization terminal 75 areelectrically connected to each other via solder or the like.

The individual sensor 71 is arranged in the storage space such that theone end of the connection terminal 60 is inserted through the insertionhole of the bottom wall 77 and the second through hole 76 d. Then, thesecond through hole 76 d and the connection terminal 60 are electricallyconnected to each other via solder or the like. As described above, theconnection terminal 60 of the individual sensor 71 is electricallyconnected via the second through hole 76 d, the wiring pattern on theintegrated wiring board 76, and the first through hole 76 c, to theenergization terminal 75.

The wiring case 72 has multiple flanges 82 for mounting the secondcurrent sensor 12 in the vehicle. The multiple flanges 82 a each have abolt hole 82 a for bolt-fixing the second current sensor 12 to thevehicle.

The wiring case 72 of the present embodiment has three flanges 82. Oneof the three flanges 82 is formed on the bottom wall 77 adjacent to theright wall 78 b. One of the remaining two flanges 82 is formed on theterminal housing 74 adjacent to the lower wall 78 d. This flange 82 isconnected integrally with the terminal block 80. The remaining oneflange 82 is formed on the opposite side to the connection part of theterminal housing 74 to the integrated housing 73.

As described above, the two of the three flanges 82 are aligned via theintegrated housing 73 and the terminal housing 74 in the x direction.The remaining one flange 82 is away from the two flanges 82 that arealigned in the x direction, in the y direction. In this manner, thethree flanges 82 form apexes of a triangle.

As described above, the one end of the connection terminal 60 projectsfrom the outer bottom surface 77 b, and the one end of the energizationterminal 75 projects from the lower surface 74 b. Further, theintegrated wiring board 76 is disposed on the outer bottom surface 77 band the lower surface 74 b. To avoid contacts with the vehicle of theone end of the connection terminal 60, the one end of the energizationterminal 75, and the integrated wiring board 76, the three flanges 82each have a leg 83 extending in the z direction. In the state where thesecond current sensor 12 is mounted in the vehicle, the one end of theconnection terminal 60, the one end of the energization terminal 75, andthe integrated wiring board 76 are separated from the vehicle, with thelegs 83, in the z direction.

<Advantageous Effects of Current Sensor>

Next, the advantageous effects of the current sensor according to thepresent embodiment will be described. As described above, the firstcurrent sensor 11 and the individual sensor 71 of the second currentsensor 12 and third current sensor 13 have equivalent configurations.Accordingly, the respective sensors achieve the similar advantageouseffects. In the following description, to avoid complications, the firstcurrent sensor 11 and the individual sensor 71 are not discriminated butmerely referred to as a current sensor. The degradation of detectionaccuracy to detect the current is suppressed with the following variousadvantageous effects.

<Magnetic Saturation of Shield>

As described above, in the first opposite end part 41 e of the firstshield 41, the length in the x direction is shorter than that of thefirst center part 41 d. Accordingly, entrance of magnetic field into thefirst opposite end part 41 e is suppressed. The permeation of magneticfield through the portions of the first center part 41 d, directlyconnected to and aligned with the first opposite end part 41 e in the ydirection (parallel portions), from one to the other of the two ends ofthe first both end part 41 e, is suppressed. As a result, magneticsaturation in the parallel portions of the first center part 41 d issuppressed. Leakage of electromagnetic noise from the first center part41 d is suppressed.

FIG. 24 shows, by schematically hatching, a region of the first shield41 easily magnetically saturated by magnetic field permeation. In FIG.24, (a) schematically shows the magnetic saturation occurring in thefirst shield without notch as a comparative configuration; and (b)schematically shows a magnetically saturated region of the first shield41 according to the present embodiment. In FIG. 24, a bold solid arrowindicates a current which flows through the electrical-conduction busbar 30.

As shown in the figure, in the first shield without notch, magneticsaturation uniformly and easily occurs. On the other hand, in the firstshield 41 in which the notches 41 c are formed, even when magneticsaturation occurs in a region other than the parallel portions of thefirst center part 41 d, the occurrence of magnetic saturation issuppressed in the parallel portions.

FIG. 25 shows a simulation result of distribution of the magnetic fieldwhich permeates the shield. In FIG. 25, (a) shows the magnetic fielddistribution in a cross section along an XXVa-XXVa line shown in FIG.24; and (b) shows the magnetic field distribution in a cross sectionalong an XXVb-XXVb line shown in FIG. 24.

Note that in FIG. 25, (a) shows a simulation result when the firstshield 41 and the second shield 42 each have a rectangular shape; and(b) shows a simulation result when the notches 41 c are formed in thefirst shield 41 and the second shield 42. The intensity of the magneticfield is expressed with coarseness/fineness of hatching. As thecoarseness of the hatching is increased, the intensity of the magneticfield becomes lower, while as the fineness of the hatching is increased,the intensity of the magnetic field becomes higher.

As it is obvious from the simulation result, when the notch 41 c isomitted, the magnetic field distributions in the first shield and thesecond shield are uniform. The intensities of the respective entiremagnetic fields in the first shield and the second shield are high. Onthe other hand, when the notches 41 c are formed, the intensities of therespective entire magnetic fields in the first shield and the secondshield are low. Especially, the intensities of magnetic fielddistributions in the respective parallel portions in the first centerpart 41 d and the second center part 42 d are low. With thisconfiguration, the leakage of the electromagnetic noise from the firstcenter part 41 d and the second center part 42 d by the magneticsaturation is suppressed.

Note that as shown in FIG. 25, the intensities of the respectivemagnetic field distributions in the first shield 41 and the secondshield 42 are different. The difference is caused since the distancebetween the first shield 41 and the electrical-conduction bus bar 30 andthe distance between the second shield 42 and the electrical-conductionbus bar 30 are different. In both of the magnetic field distributions,the intensity is low in the parallel portions, while the intensity ishigh in the other region than the parallel portions.

The parallel portions of the first center part 41 d where the magneticsaturation is suppressed, and the first sensing unit 21 and the secondsensing unit mounted on the wiring board 20, are aligned in the zdirection. Accordingly, the input of the electromagnetic noise, leakedby the magnetic saturation in the first center part 41 d, into themagnetoelectric converter 25 of the first sensing unit 21 and the secondsensing unit 22, is suppressed.

<Misalignment of Shield>

The first shield 41 is mounted on the shield support pin 57 a, and fixedvia the shield adhesive 57 e to the shield adhesion pin 57 b. The secondshield 42 is mounted on the shield support pin 57 a, and fixed via theshield adhesive 57 e to the base 51.

With this configuration, the misalignment of the first shield 41 and themisalignment of the second shield 42 respectively with respect to thesensor housing 50 do not depend on the shape variation of the shieldadhesive 57 e having fluidity upon the adhesion fixing any longer. Themisalignment of the first shield 41 and the misalignment of the secondshield 42 respectively with respect to the sensor housing 50 are causedby the manufacturing error of the sensor housing 50. It is possible toshift the factor of the misalignment of the first shield 41 and themisalignment of the second shield 42 respectively with respect to thewiring board 20 fixed to the sensor housing 50 to the manufacturingerror of the sensor housing 50. As a result, it is possible to suppressreduction of input suppression of electromagnetic noise caused by thefirst shield 41 and the second shield 42 into the magnetoelectricconverter 25.

The temperature of the shield adhesive 57 e upon the adhesion fixing ofthe first shield 41 and the second shield 42 respectively to the sensorhousing 50 is set to be higher than the temperature of the environmentwhere the current sensor is provided. The shield adhesive 57 e is cooleddown to the room temperature and is thus solidified. With thisconfiguration, in the shield adhesive 57 e, a residual stress condensingto its own center occurs at the temperature of the environment where thefirst current sensor is provided. The contact state between the firstshield 41 and the shield support pin 57 a and the contact status betweenthe second shield 42 and the shield support pin 57 a are respectivelymaintained.

With this configuration, the displacement of the first shield 41 and thedisplacement of the second shield 42 respectively with respect to thesensor housing 50 in the z direction are suppressed. In other words, thedisplacement of the first shield 41 and the displacement of the secondshield 42 respectively with respect to the wiring board 20 fixed to thesensor housing 50 in the z direction are suppressed. With thisconfiguration, the reduction of input suppression of electromagneticnoise, cased in the first shield 41 and the second shield 42 into themagnetoelectric converter 25, is suppressed.

<Misalignment of Wiring Board>

The wiring board 20 is mounted on the board support pin 56 a and isfixed via the board adhesive 56 e to the board adhesion pin 56 b.

With this configuration, the misalignment of the wiring board 20 withrespect to the sensor housing 50 does not depend on the shape variationof the board adhesive 56 e having fluidity upon the adhesion fixing anylonger. The misalignment of the wiring board 20 with respect to thesensor housing 50 is caused by the manufacturing error of the sensorhousing 50. It is possible to shift the factor of the misalignment ofthe wiring board 20 with respect to the electrical-conduction bus bar 30fixed to the sensor housing 50 to the manufacturing error of the sensorhousing 50. As a result, the variation of the measurement current whichpermeates the magnetoelectric converter 25 mounted on the wiring board20 is suppressed.

The temperature of the board adhesive 56 e upon the adhesion fixing ofthe wiring board 20 to the sensor housing 50 is set to be higher thanthe temperature of the environment where the current sensor is provided.The board adhesive 56 e is cooled down to the room temperature and isthus solidified. With this configuration, in the board adhesive 56 e, aresidual stress condensing to its own center occurs at the temperatureof the environment where the current sensor is provided. The contactstatus between the wiring board 20 and the board support pin 56 a ismaintained with the residual stress.

With this configuration, the displacement of the wiring board 20 withrespect to the sensor housing 50 in the z direction is suppressed. Inother words, the displacement of the wiring board 20 with respect to theelectrical-conduction bus bar 30 fixed to the sensor housing 50 in the zdirection is suppressed. With this configuration, the variation of themeasurement current which permeates the magnetoelectric converter 25mounted on the wiring board 20 is suppressed.

<Manufacturing Error of Wiring Board>

The first sensing unit 21 and the second sensing unit 22 are provided onthe opposing surface 20 a of the wiring board 20 with respect to theelectrical-conduction bus bar 30. With this configuration, the distancesbetween the first sensing unit 21 and the electrical-conduction bus bar30 and between the second sensing unit 22 and the electrical-conductionbus bar 30 in the z direction do not depend on the thickness of thewiring board 20 in the z direction any longer. The variation of thedistances between the sensing units and the electrical-conduction busbar 30 in the z direction, due to the manufacturing error of thethickness of the wiring board 20 in the z direction, is suppressed.

<Separation of Wiring Case and Individual Sensor>

In a case where an electrical-conduction bus bar is fixed to a housingmade of an insulating resin material, misalignment occurs in the bus barwith respect to the housing due to a manufacturing error of the housingor time deterioration such as creep of the housing. The larger thephysical constitution of the housing is, the larger the misalignment is.

As described above, the second current sensor 12 and the third currentsensor 13 have the integrated housing 73, the physical constitution ofwhich is larger than that of the sensor housing 50 of the current sensor(individual sensor 71). The current sensor is accommodated in theintegrated housing 73. The electrical-conduction bus bar 30 is fixed,not to the integrated housing 73 having the large physical constitution,but to the sensor housing 50. The magnetoelectric converter 25 detectsthe current which flows through the electrical-conduction bus bar 30.

According to the configuration, the occurrence of relative misalignmentbetween the electrical-conduction bus bar 30 and the magnetoelectricconverter 25, due to the above-described manufacturing error of thehousing or time deterioration such as creep of the housing, issuppressed.

Second Embodiment

Next, a second embodiment will be described with reference to FIG. 26and FIG. 27. The current sensors of the following respective embodimentshave many points common to the above-described embodiment. Accordingly,in the following descriptions, explanation of the common parts will beomitted, and the differences will be mainly explained. Further, in thefollowing descriptions, the constituent elements the same as theconstituent elements shown in the above-described embodiment will havethe same reference numerals.

<Extending Part at Both Ends>

In the first embodiment, the example where the second shield 42 has theextending parts 42 c, which extends in the z direction, at the two sides42 f aligned in the x direction and adjacent to the second center part42 d has been shown. In the present embodiment, as shown in FIG. 26, inthe second shield 42, the extending parts 42 c are formed at the twosides 42 f and adjacent to second opposite end parts 42 e. In FIG. 26,(a) is a perspective view for explaining the arrangement of the shield,the magnetoelectric converter, and the electrical-conduction bus bar;and (b) is a side view for explaining the arrangement of the shield,magnetoelectric converter, and the electrical-conduction bus bar.

With this configuration, the magnetoelectric field entered the secondshield 42 easily permeates via the extending parts 42 c formed at thesecond opposite end parts 42 e in the first shield 41. As schematicallyshown in FIG. 27, in the first shield 41, the permeation pathway isadjacent to the first opposite end parts 41 e. Similarly, the permeationpathway of the magnetic field in the second shield 42 is adjacent to thesecond opposite end parts 42 e.

In FIG. 27, a bold solid arrow indicates the current which flows throughthe electrical-conduction bus bar 30; a solid arrow indicates themagnetic field which permeates the first shield 41; and a broken arrowindicates the magnetic field which permeates the second shield 42. Inthe figure, an enclosed middle dot symbol indicates the magnetic fieldwhich directs from the second shield 42 toward the first shield 41 inthe z direction; and an enclosed cross symbol indicates the magneticfield which directs from the first shield 41 toward the second shield 42in the z direction.

Accordingly, the electromagnetic noise entered the second shield 42hardly flows via the second center part 42 d to the first shield 41.Similarly, the electromagnetic noise entered the first shield 41 hardlypermeates via the first center part 41 d to the second shield 42.

The second center part 42 d and the first center part 41 d are hardlymagnetically saturated respectively. As a result, the leakage of themagnetic field respectively from the second center part 42 d and thefirst center part 41 d due to magnetic saturation is suppressed.

Further, as clearly indicated in (b) of FIG. 26, the magnetoelectricconverters 25 of the first sensing unit 21 and the second sensing unit22 are positioned between the two extending parts 42 c in the ydirection. That is, the magnetoelectric converters 25 are positionedbetween the second center part 42 d and the first center part 41 d inthe z direction. Accordingly, input of the magnetic field, leakedrespectively due to magnetic saturation of the second center part 42 dand the first center part 41 d, into the magnetoelectric converters 25,is suppressed. As a result, the degradation of accuracy in themeasurement current detection is suppressed.

In the present embodiment, the example where the extending part 42 c isformed respectively on the second opposite end parts 42 e of the twosides 42 f of the second shield 42 has been shown. However, as shown in(a) of FIG. 28, for example, a configuration where the extending part 42c is also formed on the second center part 42 d of the two sides 42 f ofthe second shield 42 may be employed. Note that in the extending part 42c formed on the second center part 42 d, the length in the z directionis shorter than that of the extending part 42 c formed on the secondopposite end parts 42 e. With this configuration, the magnetic fieldentered the shield 40 permeates the end part more easily than the centerpart.

Further, as shown in (b) of FIG. 28, a configuration where the extendingpart 42 c is formed on the second opposite end parts 42 e of one of thetwo sides 42 f, and the extending part 42 c is formed on the secondopposite end parts 42 e and the second center part 42 d of the other oneof the two sides 42 f, may be employed. Note that in the other one ofthe two sides 42 f, the lengths of the extending parts 42 c, formed onthe second opposite end parts 42 e and the second center part 42 d, inthe z direction, are the same. With this configuration, the magneticfield entered the shield 40 also permeates the end part more easily thanthe center part. In FIG. 28, (a) and (b) shows a perspective view forexplaining the arrangement of the shield, the magnetoelectric converter,and the electrical-conduction bus bar.

Further, as shown in (a) of FIG. 29, a configuration where the extendingpart 42 c is formed on one of the two second opposite end parts 42 e ofone of the two sides 42 f, and on the other one of the two secondopposite end parts 42 e of the other one of the two sides 42 f, may beemployed. The extending part 42 c formed on one of the two sides 42 fand the extending part 42 c formed on the other one of the two sides 42f are away from each other respectively in the y direction and in the xdirection.

Further, a configuration where the extending part 42 c is formed on thefirst shield 41 in addition to the second shield 42 may be employed. Thefirst shield 41 has two opposing sides 41 f aligned in the x direction.For example, as shown in (b) of FIG. 29, a configuration where theextending parts 42 c are formed on the first opposite end parts 41 e ofthe two opposing sides 41 f in the first shield 41 may be employed. InFIG. 29, (a) and (b) show a perspective view for explaining thearrangement of the shield, magnetoelectric converter, and theelectrical-conduction bus bar.

As the form of the extending part 42 c which can be formed on the firstshield 41, a form equivalent to the extending part 42 c formed on thesecond shield 42 shown above may be employed. The extending part 42 cformed on the first shield 41 corresponds to an extension part.

Note that the current sensor according to the present embodiment and thefollowing embodiments include constituent elements equivalent to theconstituent elements of the current sensor described in the firstembodiment. Therefore, it goes without saying that the current sensoraccording to the present embodiment and the following embodimentsachieve the similar advantageous effects.

Third Embodiment

Next, a third embodiment will be described based on FIG. 30 to FIG. 32.

<Stress Relaxation Member>

In the present embodiment, a stress relaxation member 34 is formed inthe electrical-conduction bus bar 30 of the first current sensor 11. Thestress relaxation member 34 is formed in the first exposed part 32 andthe second exposed part 33 of the electrical-conduction bus bar 30.

As described above, the electrical-conduction bus bar 30 has the coveredpart 31 covered with the sensor housing 50. The first exposed part 32and the second exposed part 33 are respectively exposed from the sensorhousing 50, and connected integrally with the covered part 31. The bolthole 30 c for electrical and mechanical connection with the energizationbus bar 307 via the bolt is formed respectively in the first exposedpart 32 and the second exposed part 33. The stress relaxation member 34is formed respectively in the connection parts between the first exposedpart 32 and the covered part 31 and between the second exposed part 33and the covered part 31, and in the connection parts between the firstexposed part 32 and the forming part of the bolt hole 30 c and betweenthe second exposed part 33 and the forming part of the bolt hole 30 c.

As shown in FIG. 31, the stress relaxation member 34 is locally bentfrom the rear surface 30 b of the electrical-conduction bus bar 30toward the front surface 30 a. With this bending, the stress relaxationmember 34 is elastically deformable by bending with respect to a forcein the z direction applied to the electrical-conduction bus bar 30. InFIG. 31, the stress relaxation member 34 is bent like a weaving at once.The number of times of waving and the bending form are not limited tothe above described example.

As described above, the electrical-conduction bus bar 30 is bolt-fixedto the energization bus bar 307. The energization bus bar 307 of thepresent embodiment corresponds to a first terminal block 307 a and asecond terminal block 307 b shown in FIG. 32. The electrical-conductionbus bar 30 is bolt-fixed to the first terminal block 307 a and thesecond terminal block 307 b. With this configuration, the first terminalblock 307 a and the second terminal block 307 b are bridged with theenergization bus bar 307. The first terminal block 307 a and the secondterminal block 307 b are electrically connected to each other via theenergization bus bar 307. Note that in the following description, asshown in FIG. 32, the bolt inserted through the bolt hole 30 c of theelectrical-conduction bus bar 30 is denoted by a reference numeral 307c. The first terminal block 307 a and the second terminal block 307 bcorrespond to an external energization unit.

The first terminal block 307 a has a first mounting surface 307 d facingin the z direction. Similarly, the second terminal block 307 b has asecond mounting surface 307 e facing in the z direction. A fasteninghole 307 f for fastening the shaft of the bolt 307 c is formed in eachof the first mounting surface 307 d and the second mounting surface 307e. The fastening holes 307 f are opened in the first mounting surface307 d and the second mounting surface 307 e. The fastening hole 307 fextends in the z direction. In FIG. 32, (a) shows a case where thepositions of the first mounting surface and the second mounting surfacein the z direction correspond with each other; and (b) shows a casewhere the positions of the first mounting surface and the secondmounting surface in the z direction do not correspond with each other.

The rear surface 30 b of the first exposed part 32 opposes to the firstmounting surface 307 d in the z direction. The rear surface 30 b of thesecond exposed part 33 opposes to the second mounting surface 307 e inthe z direction. In this state, the first current sensor 11 is providedon the first terminal block 307 a and the second terminal block 307 b.

As shown in (a) of FIG. 32, when the positions of the first mountingsurface 307 d and the second mounting surface 307 e in the z directioncorrespond with each other, the rear surface 30 b of the first exposedpart 32 is in contact with the first mounting surface 307 d, and therear surface 30 b of the second exposed part 33 is in contact with thesecond mounting surface 307 e. In this contact state, the end of theshaft of the bolt 307 c is inserted into the bolt hole 30 c of theelectrical-conduction bus bar 30 and the fastening hole 307 f of theterminal block along the z direction. Then, the bolt 307 c is fastenedto the terminal block so as to bring the head of the bolt 307 c closerto the first mounting surface 307 d (second mounting surface 307 e). Thefirst exposed part 32 and the second exposed part 33 are held betweenthe head of the bolt 307 c and the terminal block. With isconfiguration, the first current sensor 11 is mechanically andelectrically connected to the terminal block.

On the other hand, as shown in (b) of FIG. 32, when the positions of thefirst mounting surface 307 d and the second mounting surface 307 e inthe z direction do not correspond with each other, upon contact betweenthe rear surface 30 b of the first exposed part 32 and the firstmounting surface 307 d, the rear surface 30 b of the second exposed part33 is not in contact with the second mounting surface 307 e. The secondmounting surface 307 e and the rear surface 30 b of the second exposedpart 33 are away from each other in the z direction, and a gap is formedbetween the second mounting surface 307 e and the rear surface 30 b.

In this separated state, when the shaft of the bolt 307 c is inserted inthe bolt hole 30 c and the fastening hole 307 f and the head of the bolt307 c is brought into contact with the front surface 30 a of the secondexposed part 33, a force toward the z direction acts on the secondexposed part 33.

As described above, to enhance the intensity of the measurement currentwhich permeates the magnetoelectric converter 25, the narrow part 31 ain which the length in the x direction is locally short is formed in thecovered part 31. Since the length of the narrow part 31 a in the xdirection is short, the rigidity of the narrow part 31 a is lower thanthat of other parts. The narrow part 31 a can be easily deformed.

Accordingly, when the force toward the z direction upon fastening of thebolt 307 c acts on the second exposed part 33 as described above, thereis a fear of deformation of the narrow part 31 a due to the force. Thereis a fear of position displacement of the narrow part 31 a in the sensorhousing 50. Even when the narrow part 31 a is not formed in the coveredpart 31, there is a fear of position displacement of the covered part 31in the sensor housing 50. With the position displacement, there is afear of change of distribution of the measurement current whichpermeates the magnetoelectric converter 25.

As described above, the stress relaxation member 34 is formed in each ofthe first exposed part 32 and the second exposed part 33. Accordingly,with the above-described positional difference in the z directionbetween the first mounting surface 307 d and the second mounting surface307 e, even when there is a gap between the second mounting surface 307e and the rear surface 30 b of the second exposed part 33, the stressrelaxation member 34 is elastically deformed in correspondence with theforce of the bolt 307 c in the z direction. With this configuration, thedeformation of the narrow part 31 a is suppressed. The positiondisplacement of the narrow part 31 a in the sensor housing 50 issuppressed. As a result, the change of the distribution of themeasurement current which permeates the magnetoelectric converter 25 issuppressed. The degradation of accuracy in the measurement currentdetection is suppressed.

Note that the length (thickness) of the stress relaxation member 34between the front surface 30 a and the rear surface 30 b is equal to therespective thicknesses of the covered part 31, the first exposed part32, and the second exposed part 33. With this configuration, differentfrom a configuration where, e.g. the thickness of the stress relaxationmember is locally thin in comparison with the thicknesses of the coveredpart and the exposed part, local heat generation in the stressrelaxation member 34 by the current energization is suppressed. As aresult, life reduction of the electrical-conduction bus bar 30 issuppressed.

Fourth Embodiment

Next, a fourth embodiment will be described with reference to FIG. 33 toFIG. 35. In FIG. 33, (a) shows a top view of the electrical-conductionbus bar; and (b) shows a side view of the electrical-conduction bus bar.In FIG. 34, (a) shows the position of the wiring board 20 on which therespective magnetoelectric converters 25 of the first sensing unit 21and the second sensing unit 22 are mounted and the position of theelectrical-conduction bus bar 30; (b) shows displacement of the wiringboard 20 with respect to the electrical-conduction bus bar 30; and (c)shows a magnetic field which permeates the respective magnetoelectricconverters 25 of the first sensing unit 21 and the second sensing unit22.

<Difference Cancellation>

In the first embodiment, the example where the respectivemagnetoelectric converters 25 of the first sensing unit 21 and thesecond sensing unit 22 are aligned in the y direction has been shown. Inthe present embodiment, as indicated with a broken line in FIG. 33, therespective magnetoelectric converters 25 of the first sensing unit 21and the second sensing unit 22 are aligned in the x direction. Themagnetoelectric converter 25 of the first sensing unit 21 corresponds toa first magnetoelectric converter. The magnetoelectric converter 25 ofthe second sensing unit 22 corresponds to a second magnetoelectricconverter.

The two magnetoelectric converters 25 are symmetrically arranged via thesymmetry axis AS. The positions of the two magnetoelectric converters 25in the y direction and the position of the symmetry axis AS (centerpoint CP) in the y direction are the same. Accordingly, the twomagnetoelectric converters 25 are aligned via the center point CP in thex direction.

Further, the distances between the two magnetoelectric converters 25 andthe covered part 31 in the z direction are the same. The covered part 31and the narrow part 31 a form a line-symmetrical shape via the symmetryaxis AS. Accordingly, measurement currents, having different z-directioncomponents but equivalent x-direction components, permeate the twomagnetoelectric converters 25. The absolute values of electric signalsoutputted from the two magnetoelectric converters 25 are equivalent toeach other.

As described above, the covered part 31 is covered with the base 51 ofthe sensor housing 50. The wiring board 20 on which the twomagnetoelectric converters 25 are mounted is mounted on the boardsupport pin 56 a formed on the sensor housing 50. Accordingly, thedisplacement of the wiring board 20 in the z direction is regulated withthe board support pin 56 a.

However, the wiring board 20 is fixed via the board adhesive 56 e to theboard adhesion pin 56 b. In the board adhesive 56 e, time deteriorationsuch as creep or expansion due to change of the environmentaltemperature may occur. There is a fear of displacement of the wiringboard 20 relatively in the x direction and the y direction with respectto the covered part 31.

When the wiring board 20 is displaced in the y direction, with theabove-described symmetrical arrangement of the two magnetoelectricconverters 25 in the x direction, the x-direction component of themeasurement currents which permeate the two magnetoelectric converters25 is not changed. However, as shown in FIG. 34, when the wiring board20 is displaced in the x direction, the x-direction component of themeasurement currents which permeate the two magnetoelectric converters25 is changed. As a result, the absolute values of the electric signalsoutputted from the two magnetoelectric converters 25 are not equivalentto each other any longer.

In FIG. 34, a broken line indicates the placement locations of the twomagnetoelectric converters 25 with respect to the electrical-conductionbus bar 30. An alternate long and short dash line indicates the symmetryaxis AS passing through the center point CP of the electrical-conductionbus bar 30. An alternate long and two short dashes line indicates thepositions of the two magnetoelectric converters 25 displaced withrespect to the electrical-conduction bus bar 30. An outlined arrowindicates the direction of the displacement of the wiring board 20 onwhich the two magnetoelectric converters 25 are mounted, caused with theboard adhesive 56 e, with respect to the electrical-conduction bus bar30. In (a) and (b) of FIG. 34, a solid arrow indicates the magneticfield which passes through the magnetoelectric converter 25. In (c) ofFIG. 34, a solid arrow indicates the direction of change of the magneticfield which permeates the magnetoelectric converter 25.

As described above, both of the two magnetoelectric converters 25 aremounted on the wiring board 20. Even when the relative positions of thewiring board 20 and the covered part 31 in the x direction are changedby deformation of the board adhesive 56 e as described above, therelative distance between the two magnetoelectric converters 25 mountedon the wiring board 20 is not changed. Accordingly, when the relativepositions of the wiring board 20 and the covered part 31 are changed inthe x direction by the deformation of the board adhesive 56 e, one ofthe two magnetoelectric converters 25 is closer to the symmetry axis AS,while the other one of the two magnetoelectric converters 25 is awayfrom the symmetry axis AS. The perspective distances are equivalent toeach other. In (b) of FIG. 34, the perspective distance is denoted by A.

As shown in (c) of FIG. 34, the measurement current which permeates oneof the two magnetoelectric converters 25 is reduced, while themeasurement current which permeates the other one of the twomagnetoelectric converters 25 is increased. It is expected that thedecrement and the increment of the measurement currents which permeatethe two magnetoelectric converters 25 become equivalent to each other.In (b) of FIG. 34, the change amount of the measurement current isindicated as AB.

In the present embodiment, the polarity of the electric signalsoutputted from the two magnetoelectric converters 25 is inverted. Theinversion of the polarity is realized by, for example as shown in FIG.35, reversing the arrangement of the first magnetoresistive effectelement 25 a and the second magnetoresistive effect element 25 b in thetwo magnetoelectric converters 25. Otherwise, it is possible to invertthe polarity of the two electric signals by, more simply, reversing theinverted input terminal and the non-inverted input terminal of thedifferential amplifier 25 c shown in FIG. 7 in the first sensing unit 21and the second sensing unit 22.

As described above, the electric signals, having absolute values ofincrement/decrement equivalent to each other, and different polarities,are outputted from the two magnetoelectric converters 25. The twoelectric signals generated respectively with the first current sensor 11are inputted into the battery ECU 801. The two electric signalsgenerated in the second current sensor 12 and the third current sensor13 are inputted into the MG ECU 802.

The battery ECU 801 and the MG ECU 802 take the difference between thetwo electric signals. Assuming that the absolute values of the electricsignals outputted from the two magnetoelectric converters 25 are B, andthat the absolute values of change amounts of the electric signals dueto the displacement are ΔB, as the difference processing,B+ΔB−(−(B−ΔB))=2B holds. Otherwise, as the difference processing,B−ΔB−(−(B+ΔB))=2B holds. “+” corresponds to one of the first polarityand the second polarity, and “−” corresponds to the other one of thefirst polarity and the second polarity.

The decrement and the increment of the electric signal caused by thechange of the relative positions of the wiring board 20 and the coveredpart 31 due to the above-described deformation of the board adhesive 56e are cancelled by performing the difference processing in this manner.The battery ECU 801 and the MG ECU 802 correspond to a difference part.

Note that as shown in FIG. 36, for example, a configuration where adifference circuit 29 to take the difference between the outputs fromthe two magnetoelectric converters 25 is mounted on the wiring board 20may be employed. The first output wiring 20 d and the second outputwiring 20 e are connected to the inverted input terminal and thenon-inverted input terminal of the difference circuit 29. In this case,the difference circuit 29 corresponds to the difference part.

The above-described change of the relative positions of the wiring board20 and the covered part 31 in the x direction may be caused, not only bythe above-described deformation of the board adhesive 56 e, but also byvibration by external stress which acts on the vehicle or driving of theengine 600 and the like. However, even when the relative positions ofthe wiring board 20 and the covered part 31 in the x direction arechanged by these factors, the difference between the two electricsignals outputted from the two magnetoelectric converters 25 is taken asdescribed above. With this configuration, the decrement and theincrement of the electric signals by change of the relative positions ofthe wiring board 20 and the covered part 31 are cancelled. Accordingly,the degradation of detection accuracy of the measurement magnetic fieldis suppressed.

Fifth Embodiment

Next, a fifth embodiment will be described with reference to FIG. 37 andFIG. 38.

<Anisotropy of Magnetic Permeability>

In the first embodiment, the example where the first shield 41 and thesecond shield 42 are respectively manufactured by press-joining multipleflat plates made of a soft magnetic material has been shown. In thepresent embodiment, the first shield 41 and the second shield 42 arerespectively manufactured by rolling magnetic steel.

As described in the first embodiment, it is possible to provide themagnetic permeability of the shield with anisotropy by specifying therolling direction of the magnetic steel. In the present embodiment, therolling direction of the first shield 41 and the second shield 42 isalong the z direction. With this configuration, the magneticpermeability of the first shield 41 and the second shield 42 hasanisotropy. Note that the manufacturing method of the first shield 41and the second shield 42 is not limited to the above-described example.The first shield 41 and the second shield 42 may be manufactured with amaterial, the magnetic permeability of which has anisotropy. Further, itmay be configured such that the magnetic permeability of one of thefirst shield 41 and the second shield 42 has anisotropy.

As described in FIG. 37, in the second current sensor 12 and the thirdcurrent sensor 13, the respective individual sensors 71 are aligned inthe x direction. The first shield 41 and the second shield 42 of therespective individual sensors 71 are alternately aligned in the xdirection. In this configuration, the directions of the magnetic-fielddetection of the magnetoelectric converters 25 of the individual sensor71 are the z direction and the y direction. Note that a configurationwhere, in two individual sensors 71 aligned in the x direction, thefirst shield 41 of the one of the two individual sensors 71 and thesecond shield 42 of the other one of the two individual sensors 71 maybe bundled together as one may be employed.

In the configuration where the multiple individual sensors 71 arealigned in the x direction, the measured magnetic field emitted from theelectrical-conduction bus bar 30 of one individual sensor 71 becomesexternal noise to the other individual sensor(s) 71. The external noiseis formed in a ring shape in a plane regulated with the x direction andthe z direction about the electrical-conduction bus bar 30. The externalnoise has components along the x direction and the z direction. In thismanner, in the environment of the configuration, the external noisealong the x direction and the z direction easily permeates theindividual sensor 71.

FIG. 37 shows two individual sensors 71. The measurement current flowsthrough one of the two individual sensor 71 having theelectrical-conduction bus bar 30 with an enclosed cross symbol. Themeasured magnetic field is emitted from this electrical-conduction busbar 30. To the adjacent individual sensor 71, the measured magneticfield emitted from the electrical-conduction bus bar 30 with theenclosed cross symbol is electromagnetic noise. FIG. 37 indicates themagnetic field with an arrow.

As described above, the first shield 41 and the second shield 42respectively have anisotropy in the z direction. Accordingly, thecomponent of the external noise along the z direction attempts to enterthe first shield 41 and the second shield 42 respectively. On the otherhand, the component of the external noise along the x direction does notdepend on the anisotropy of the first shield 41 and the second shield 42any longer. The component along the x direction attempts to permeate themagnetoelectric converter 25.

For example, when the magnetic field indicated with a broken arrow inFIG. 37 attempts to pass through the magnetoelectric converter 25, thecomponent of the magnetic field along the z direction actively attemptsto pass through the first shield 41 and the second shield 42respectively. However, the component of the magnetic field in the xdirection somewhat remains. Accordingly, the component of the magneticfield in the x direction attempts to permeate the magnetoelectricconverter 25.

On the other hand, the detecting directions of measured magnetic fieldof the magnetoelectric converter 25 are the z direction and the ydirection. The magnetoelectric converter 25 does not detect the magneticfield in the x direction. Even when the above-described component of themagnetic field in the x direction permeates the magnetoelectricconverter 25, the degradation of detection accuracy of the measurementmagnetic field, due to the permeation of the electromagnetic noise, issuppressed.

The alignment of the individual sensors 71 is not limited to theabove-described example. For example, as shown in FIG. 38, aconfiguration where the individual sensors 71 are aligned in the xdirection is conceivable. In this configuration, the first shields 41,the second shields 42, and the magnetoelectric converters 25, of theindividual sensors 71, are aligned in the x direction. Themagnetic-field detection directions of the magnetoelectric converter 25of the individual sensor 71 are the x direction and the y direction. Inthis configuration, it may be configured such that the first shields 41of the multiple individual sensors 71 aligned in the x direction arebundled together as one. Similarly, it may be configured such that thesecond shields 42 of the multiple individual sensors 71 are bundledtogether as one.

FIG. 38 also shows two individual sensors 71. The measurement currentflows through one of the two individual sensor 71 having theelectrical-conduction bus bar 30 with an enclosed cross symbol. FIG. 38also indicates the magnetic field with an arrow. The magnetic field hascomponents along the x direction and the z direction. Accordingly, theconfiguration has an environment where the external noise along the xdirection and the z direction easily permeates the individual sensor 71.

In this configuration, the magnetic permeability of the first shield 41and the second shield 42 in the x direction is higher than that in the ydirection. Accordingly, the component of the external noise along the xdirection attempts to enter the first shield 41 and the second shield 42respectively. On the other hand, the component of the external noisealong the z direction does not depend on the anisotropy of the firstshield 41 and the second shield 42 any longer. The component along the zdirection attempts to permeate the magnetoelectric converter 25.

For example, when the magnetic field indicated with a broken arrow inFIG. 38 attempts to pass through the magnetoelectric converter 25, thecomponent of the magnetic field along the x direction actively attemptsto pass through the first shield 41 and the second shield 42respectively. However, the component of the magnetic field in the xdirection somewhat remains. Accordingly, the component of the magneticfield in the z direction attempts to permeate the magnetoelectricconverter 25.

The detecting directions of the measurement magnetic field of themagnetoelectric converter 25 are the z direction and the y direction.The magnetoelectric converter 25 does not detect the magnetic field inthe z direction. Even when the above-described component of theelectromagnetic noise in the z direction permeates the magnetoelectricconverter 25, the degradation of detection accuracy of the measuredmagnetic field, due to the permeation of the electromagnetic noise, issuppressed.

The embodiments of the present disclosure have been explainedhereinabove. The present disclosure is not limited to theabove-described embodiments, but various changes can be made andimplemented within the gist of the present disclosure.

(First Modification)

In the first embodiment, the example where the notches 41 c are formedat the four corners of the first shield 41 has been shown. In thisexample, in the first opposite end part 41 e of the first shield 41, thelength in the x direction is shorter than that of the first center part41 d. The extending part 42 c is formed in the second shield 42.

As shown in FIG. 39, a configuration where the notches 41 c are formedat the four corners of each of the first shield 41 and the second shield42 may be employed. In the second opposite end part 42 e, the length inthe x direction is shorter than that of the second center part 42 d. Asshown in (b) of FIG. 39, the magnetoelectric converters 25 of the firstsensing unit 21 and the second sensing unit 22 mounted on the wiringboard 20 are positioned between the first center part 41 d and thesecond center part 42 d. In FIG. 39, (a) shows a perspective view forexplaining the arrangement of the shield, the magnetoelectric converter,and the electrical-conduction bus bar; and (b) is a side view forexplaining the arrangement of the shield, the magnetoelectric converter,and the electrical-conduction bus bar.

Further, as shown in (a) of FIG. 40, it may be configured such that theextending part 42 c and the notch 41 c are not formed in the secondshield 42. As shown in (b) of FIG. 40, a configuration where the notches41 c are formed at two of the four corners of the first shield 41 may beemployed. Note that in (b) of FIG. 40, two notches 41 c are aligned inthe x direction. In FIG. 40, (a) and (b) are perspective views forexplaining the arrangement of the shield, the magnetoelectric converter,and the electrical-conduction bus bar. As shown above, the formingposition of the notch 41 c is not particularly limited as long as thelength of the first both end part 41 e of the first shield 41 in the xdirection is shorter than that of the first center part 41 d.

(Second Modification)

In the first embodiment, the example where the integrated housing 73 hasthe bottom wall 77 and the peripheral wall 78, and the multipleindividual sensors 71 are accommodated in the storage space provided bythe bottom wall 77 and the peripheral wall 78 of the integrated housing73, has been shown. However, as shown in FIG. 41 to FIG. 43, it may beconfigured such that the integrated housing 73 does not have theperipheral wall 78. In this case, the individual sensor 71, rotated at90°, is provided with respect to the bottom wall 77. Thus, the frontsurface 30 a and the rear surface 30 b of the electrical-conduction busbar 30 in the individual sensor 71 respectively face in the z direction.The one surface 41 a and the rear surface 41 b of the first shield 41respectively face in the z direction. Similarly, the one surface 42 aand the rear surface 42 b of the second shield 42 respectively face inthe z direction. The detection directions of the magnetoelectricconverters 25 of the individual sensor 71 are the x direction and the ydirection.

With this configuration, as shown in FIG. 38, the first shields 41 ofthe multiple individual sensors 71 are aligned in the x direction. Thesecond shields 42 of the multiple individual sensors 71 are aligned inthe x direction. The magnetoelectric converters 25 of the multipleindividual sensors 71 are aligned in the x direction.

Note that in FIG. 42, (a) shows a top view of the second current sensor;(b) shows a front view of the second current sensor; and (c) shows abottom view of the second current sensor. In FIG. 43, (a) shows a sideview of the second current sensor; and (b) shows a front view of thesecond current sensor. (b) of FIG. 42 and (b) of FIG. 43 show the samefigure.

In the present modification, bolt holes, the number of which is the sameas the number of the individual sensors 71, are formed along the zdirection in the terminal block 80. The bolt hole 30 c is formed in thesecond exposed part 33 of the individual sensor 71. The bolt is insertedthrough the bolt hole in the terminal block 80, the bolt hole 30 c inthe second exposed part 33, and the bolt hole formed in the wireterminal. Further, the nut is fastened to the end of the bolt. The nutis fastened to the bolt from the end of the bolt shaft toward the bolthead. The second exposed part 33 and the wire terminal are held betweenthe bolt head and the terminal block 80. With this configuration, thesecond exposed part 33 and the wire terminal are brought into contact,and electrically and mechanically connected to each other.

Third Embodiment

As shown in the first embodiment, the rib 52 a is formed in the sensorhousing 50 of the first current sensor 11. Similarly, as shown in FIG.44, the rib 52 a may be formed in the sensor housing 50 of theindividual sensor 71. A guide part 72 a for insertion of the individualsensor 71 into the wiring case 72 may be formed on the bottom wall 77 ofthe integrated housing 73. The guide part 72 a forms a groove having ahollow part in a similar shape to that of the rib 52 a. The guide part72 a is opened in the z direction. The rib 52 a is passed via theopening into the hollow part of the guide part 72 a. With thisconfiguration, the individual sensor 71 is easily assembled to theintegrated housing 73 of the individual sensor 71. Note that in themodification shown in FIG. 44, a groove 77 c for providing theprotruding end of the connection terminal 60 in the individual sensor 71is formed in the bottom wall 77.

(Fourth Modification)

As schematically shown in (a) of FIG. 45, in the respective embodiments,the example where the individual sensors 71 are provided on the U phasestator coil and the V phase stator coil of the motor has been shown. Inthe example, these individual sensors 71 have the first sensing unit 21and the second sensing unit 22.

However, as schematically shown in (b) of FIG. 45, a configuration wherethe individual sensors 71 are provided on the U phase stator coil, the Vphase stator coil, and the W phase stator coil of the motor may beemployed. These individual sensors 71 may only have the first sensingunits 21.

As described above, in the three phase stator coils, based on thecurrents which flow through the two stator coils, the remaining onecurrent can be detected. Accordingly, based on outputs from two of thefirst sensing units 21 of the three individual sensors 71 provided onthe three phase stator coils, the current which flows through theremaining one stator coil can be detected. Further, with the firstsensing unit 21 of the individual sensor 71 provided on this remainingone stator coil, the current which flows through the remaining onestator coil can be detected. It is possible to determine whether or notan abnormality occurs in one of the two stator coils by comparing thetwo detected currents.

(Other Modifications)

In the respective embodiments, the example where the current sensor isapplied to the in-vehicle system 100 which forms a hybrid system hasbeen shown. However, the in-vehicle system to which the current sensoris applied is not limited to the above-described example. For example,the current sensor may be applied to the in-vehicle system of anelectric vehicle or an engine vehicle. The system to which the currentsensor is applied is not particularly limited.

While only the selected exemplary embodiments and examples have beenchosen to illustrate the present disclosure, it will be apparent tothose skilled in the art from this disclosure that various changes andmodifications can be made therein without departing from the scope ofthe disclosure as defined in the appended claims. Furthermore, theforegoing description of the exemplary embodiment and examples accordingto the present disclosure is provided for illustration only, and not forthe purpose of limiting the disclosure as defined by the appended claimsand their equivalents.

What is claimed is:
 1. A current sensor comprising: anelectrical-conduction member through which a measurement current to bemeasured flows; a magnetoelectric converter that converts a measurementmagnetic field caused by a flow of the measurement current into anelectric signal; and a shield that restricts an electromagnetic noiseinto the magnetoelectric converter, wherein the shield includes a firstshield and a second shield each having a plate shape, the first shieldand the second shield being arranged such that surfaces are opposed toand spaced away from each other, a part of the electrical-conductionmember and the magnetoelectric converter are located between the surfaceof the first shield and the surface of the second shield, the part ofthe electrical-conduction member located between the first shield andthe second shield extends in an extension direction that is along thesurface of the first shield, the first shield and the second shield eachhave a center part and opposite end parts on opposite sides of thecenter part in the extension direction, the center part of at least oneof the first shield and the second shield has a length greater thanlengths of the opposite end parts of the at least one of the firstshield and the second shield in a lateral direction that is along thesurface of the first shield and perpendicular to the extensiondirection, and the magnetoelectric converter is located between theopposite end parts of the first and second shields in the extensiondirection.